The future still isn't what it used to be: Vannevar Bush

(According to Blogger, this is the 700th post on this blog, which seems like a completely arbitrary milestone to note, but I noticed it nonetheless, so now you get to. You're welcome.)

Vannevar Bush casts something of a long shadow. He held several high-level technology-related posts in the FDR and Truman administrations, had a long and distinguished academic career at MIT and elsewhere, and won several prestigious awards, including the National Medal of Science. His students included Claude Shannon, whose work in information theory is still directly relevant, and Frederick Terman, who was influential in the development of what we now call Silicon Valley (I used to work fairly near Terman Drive in Palo Alto).

Bush is also often credited with anticipating the World-Wide Web in his Atlantic Monthly article As We May Think. Since I've been comparing early visions of the Web with what actually happened, I thought I'd take a look. I've linked to the ACM version rather than the Atlantic's version, which may or may not even be online, since the ACM version highlights the relevant passages. Though there's a Wikipedia page on the piece, I've deliberately skipped it in favor of Bush's original text (with the ACM's highlights).

Two things jump out immediately, neither directly relevant to the web:

• The language is relentlessly gendered. Men do science. Girls [sic] sit in front of keyboards typing in data for men of science to use in their work. A mathematician is a particular kind of man, technology has improved man's life, and so forth. Yes, this is 1945, and we expect a certain amount of this, but from what I can tell Bush's style stands out even for the time. I mention this mainly as a heads-up for anyone who wants to go back and read the original piece -- which I do nonetheless recommend.
• There is an awful lot of technical detail about technologies that would be obsolete within a couple of decades, and in several cases nearly fossilized by the dawn of the Internet in the 1970s. Bush speculates in detail about microphotography, facsimile machines, punch cards, analog computers, vacuum tubes, photocells and on and on for pages. Yes, all of these still existed in the 1970s (I spent many an hour browsing old newspapers and magazines on microfilm as a kid), but digital technology would make most if not all of them irrelevant before much longer. As far as predicting the technology underpinning the web, Bush's record is nearly perfect: If he speculated about it, it almost certainly isn't relevant to today's web.

Two thoughts on this. First, it's almost impossible to speculate about the future without mentioning at least something that will be hopelessly out of date by the time that future arrives. In our own time, all we have are the tools and mental models of the world of that time. I don't fault Bush for thinking about the future in terms of photographic storage, and I don't this takes anything away from his thoughts on the "Memex", which is what people are referring to when they talk about Bush anticipating the web.

I just wish he hadn't done nearly so much of it. Alan Turing's Computing Machinery and Intelligence spends two sentences on the idea of using a teleprinter so that it's not obvious whether there's a human or machine on the other end of the conversation, and one of those sentences just says that this is only one possible approach. That seems about right for that paper. In Bush's case, I could see a few paragraphs about how to store large amounts of information (for those days, at least) on film or magnetic media, and so forth. The article would have been much shorter, but no less interesting.

Second it's worth noting how many things were possible with mid 1900s technology. You could convert, both ways, between sound, image and video (in the sense of moving images) on the one hand and electrical signals on the other. You could store electrical signals magnetically. You could communicate them over a distance. You could store digital information in a variety of forms, including the famous punched cards, but also magnetically.

There were ways to produce synthesized speech and read printed text. Selecting machines could do boolean queries on data (Bush gives the example of "all employees who live in Trenton and know Spanish"). Telephone switching networks could connect any of millions of phones to any other in about the time it took to dial (and less time than it sometimes takes my phone to set up a call using my WiFi). Logic gates existed. For that matter, the first general-purpose digital computer, the ENIAC, existed in 1945 and Bush would certainly have known about its development.

In other words, even in 1945, Bush isn't drawing on a blank canvas. He's trying to pull existing pieces of technology together in a new way in order to deal with what was, even at the time, an overwhelming surplus of information. The gist of the argument is "If we make these existing technologies smaller, faster and cheaper, and put them together in this particular way, we can make it easier to deal with all this information."

The particular problem Bush is really interested in isn't so much storing information as retrieving it ("selecting" as Bush says). This is totally understandable for a national science adviser who had until recently been working on one of the largest technological efforts to date (the Manhattan Project). Bush cites Gregor Mendel's work having been essentially unknown until decades after the fact as just one example of a significant advance nearly being lost because no one knew about it, even though it was there to be found. Bush's desire to prevent this sort of thing in the future is palpable.

Bush mentions traditional indexing systems that can find items by successively narrowing down the search space (everything starting with 'F', everything within that with second letter 'i' ... ah, here it is, Field Notes on the Web), but he's much more interested in following a trail of connections from one document to another. That is, he's envisioning a vast collection of documents traversable by following links between them. That's the world-wide web. Ok, we're done.

Except ...

Bush sees the Memex as literally a piece of furniture, looking pretty much like a desk but with a keyboard attached along with various projection screens and a few other attachments. Inside it is a store of microfilmed documents together with some writable film, which takes up a small portion of the space under the desk, and a whole bunch of machinery to be named later, taking up most of the space.

Associated with each document is a writable area containing some number of code spaces, each of which can hold the index code of a document. There's also a top-level code book to get you started, and when you add a new document, you add it to the code book. To be honest, this seems a bit tedious.

To link two documents together, you pull them both up, one on one projection screen and the other on the other, and press a button. This writes the index code for each document in the other's next open code space. The next time you pull up either of the documents, you can select a code space and pull up the document with that code.

Codes are meant to have two parts: a human-readable text code and a "positional" numeric code (probably binary or maybe decimal). Linking this post to Bush's article might add "Bush-as-we-may-think" to a code space for this post, along with (somewhere offscreen) the numeric index for Bush's article, and "Field-notes-future-ramblings-Bush" to a code space on Bush's article (along with the numeric code for this post). At that point you've got one link in a presumably much larger web.  Actually, you have two links, or one-bidirectional link if you prefer. Not quite Xanadu's transclusion, but arguably closer than what we actually have.

Pretty webby, except ... coupla things ...

For one thing, this is all happening on my Memex. My copy of this post is linked with my copy of Bush's article. Yours remains untouched. If there's a way of copying either content or links from one Memex to another, I didn't catch it. Bush's description of how document linking works is hand-wavy enough that it wouldn't be particularly more hand-wavy to talk about a syncing mechanism (and/or an update mechanism), but I doubt Bush was thinking in that direction.

Bush seems to be thinking more about a memory aid for an individual person (or possibly a household or small office/laboratory). Functionally, it's a personal library with much larger capacity and the ability to leave trails among documents. It's certainly an interesting idea, but it misses the "world-wide" part. When I link to the ACM's version of Bush's paper, the link is from my blog to the ACM's site. If you write something and link it to Bush's paper, we're pointing at the same thing, not separate copies of it, and we're pointing to a thing that might be stored anywhere in the world (and someplace else next time we access it).

In the same post I mentioned above, I talk about a couple of features that make the web the web, particularly that a link can be dangling -- pointing to nothing -- and it can become broken -- you pointed at a page, but that page is no longer there (early posts on this blog are full of these, though at the time it wasn't clear whether rotting links would be an issue as storage got cheaper; they are). There's also some ambiguity as to what exactly a link is pointing to. If I point to the front page of a news site, for example, the contents on the other end of that link will probably be different tomorrow. In other cases, it's worth going to some effort to ensure the contents don't change significantly.

These may seem like bugs at first glance, but for the most part, they're features, because the flexibility they provide allows the web to be decoupled. I can do what I like with my site without caring or even knowing what links to it. Since a Memex is a closed system, none of this really applies. On the one hand, it's not a problem, but on the other hand, it's not a problem because a Memex is not a distributed system, which the web as we know it very much is.

Finally, the mechanism of linking is noticeably different from what HTML does. You have a pair of links between documents (or maybe pages within documents, given that that's what's on the screen when you press the "link" button?). An HTML link is between a particular piece of the source document to, in the general case, a particular anchor on the destination document. To be fair, this doesn't seem like an essential difference. You could imagine a Memex with a linking mechanism that goes from a piece of one document to a piece of another, which would be much more like an HTML link (and, arguably, more like a Xanadu transclusion).

[Really, though, an HTML link points to whatever the server on the other end serves up in response to that particular URL. The resulting page is often, one way or another, maintaining live connections to any number of other servers and updating its appearance accordingly. In writing the post, I implicitly assumed that everything was static text, since that was the world Bush was dealing in. The dynamic nature of real web resources is a whole separate dimension. The point here is that even without that Memex isn't really the Web -- D.H. April 2025]

So did Vannevar Bush anticipate the web by nearly half a century?

I think the fair answer is "not really", because the distributed, dynamic nature of the web is critical.

Did he anticipate the idea of an interconnected web of documents? I think the fair answer is "sorta". Again, actual web links are one-directional and non-intrusive. You can link from document A to document B without doing anything at all to document B or its associated metadata. You don't need a backlink and you generally won't have one.

This one-way form of link was not a new idea. Documents have been referencing each other forever. Bush's notion of linking is different from an HTML link, and since an HTML link is structurally the same as a reference in a footnote in a book, it's different from that as well.

In other words, the original idea in Bush's work is more an evolutionary dead end than an innovation. A pretty interesting dead end, but a dead end just the same.

Postscript:

There's one more thing that I'd been meaning to mention but, embarrassingly enough, forgot to: search. Bush is quite right in saying that people access information by content, but in the Memex world everything eventually boils down to an index number. You access document 12345, not "any documents mentioning Memex" or whatever.

Search is probably the aspect of the web with the least precedent in mid-1900s technology. There were ways to attach index numbers to things, or even content tags, and retrieve them, with a minimum of human intervention. Bush goes into those at length. But if you wanted to get to something by what was in it, you needed a person for that, if only to add indexing information. Indeed, Memex is aimed directly at making it easier for a human to do that task, by making it easy to leave a trail of breadcrumbs a human could easily follow.

It would be almost a half-century before documents could be easily accessed by way of what was in them.

Oh, and also ... in Bush's vision, linking documents together would be a frequent activity for anyone using a Memex. In today's web, not so much, except, I think, in the particular case of re-whatevering a piece of social media content. I think the reason for that is also search (see this early post for a take on that).

On to the next milestone

It looks like I ended up adding a few more posts to the original five (four real posts plus the birthday post).  Counting this one, that'll make ten in all (but only eight real posts).

That seems like enough for now.  I'll probably come back later and edit for typos and stylistic blunders, and maybe add some missing links, but I make no promise as to what will appear here for the next while.  As usual, I might post again tomorrow, or not for months.  I probably will post again at some point, but if not, the 600+ existing posts aren't going anywhere.

It does seem like someone (or someone's web crawler, at least) has been reading, and that's cool.  If you've read and enjoyed, so much the better.

Cheers!

Happy 10th, Field Notes

On August 23, 2007 I published the very first post on this blog.  As I've said before, the original aim was to join the blogging community and, frankly, improve my job prospects.  I would be hooked into the network of tech bloggers, doors would open and life would be good.

As it turned out, this didn't happen, but doors ended up opening, life is good and I'm grateful.

The blog, for its part, has evolved on its own.  My original aim was to be fairly technical, but that soon fell by the wayside.  Not that I never get technical, just that I'm not particularly writing for fellow geeks.  Rather, I'm writing for that hypothetical "intelligent layperson", someone who's not deeply versed in the field but knows a thing or two and is interested to find out a bit more.  If that's you, and you've been able to find out a bit more, I'm glad to have helped.

I used to have a self-imposed quota of ten posts a month.  That was good in that it prompted me to post, but eventually it felt like I was just doing it to do it.  This being the tenth anniversary, and with the quota in mind, it would make sense to put together a sudden flurry of ten posts to mark the occasion.  So I've put together five, counting this one.

Enjoy!

Now available on its own domain

At least for the next year, more or less, you'll be able to reach this blog not only at fieldnotesontheweb.blogger.com, but at plain old fieldnotesontheweb.com.  I doubt this will really affect anyone's life greatly, but hey, why not?

A belated Happy Birthday

Yikes, this is a bit casual even for the new, even-more-casual Field Notes [Heh ... I think the current record is now 27 Aug to 14 Dec 2015, which would include a Field Notes birthday -- D.H. Dec 2015].  For months I'd realized that post 500 and the third anniversary of the first Note would come close together, but I got so caught up in spinning up the new blog after post 500 that I forgot all about the date, even though I posted just one day afterwards.

In the new spirit of apathy, I won't hold forth as I did in years past, but I would at least like to note the occasion, if only a bit after the fact.

My, how time files

Somewhat over a year ago I posted post number 300 and said I probably wouldn't make much of a production until I hit a more significant milestone.

This is post 500 and, having mulled this whole "blog" thing over, I've come to a few small conclusions:

• After 500 posts and nearly three years I'm pretty well convinced I can write a blog.
• The last couple of months have seen a mad scramble at month-end to make my self-imposed and arbitrary ten-post-a-month quota
• I still enjoy writing Field Notes, but there are also other things I'd like to write and my time is limited.
• Somewhat to my surprise, I still enjoy reading this blog, despite feeling that I must have beaten most of the major themes to death by now.

So ... I'm not sure exactly what to do next, but one decision did jump out: Drop the ten-post-a-month thing. It's good to have a goad to encourage putting something down, but at this point in the game just producing posts doesn't seem like a very meaningful end in itself.

That doesn't necessarily mean I'll be posting less. I might, I might not. The next post might be tomorrow (not unlikely) or in a year (much less likely), but there will definitely be a next post, and one after that ... Will there be a post 1000? I have no idea.

One thing I probably will do is go back and re-read the whole blog from start back to real time and do a bit of gardening along the way. That will almost certainly produce a few "where are they now?" followups -- maybe a year or two is a long time on the web after all.

As always, I thank anyone reading this and in particular anyone following the blog regularly for your time and attention, and hope that you enjoy it at least as much as I.

[Hmm ... re-reading the blog ... now there's an idea.  Five years later I still hadn't done it, but I'm doing it now, slowly, in reverse chronological order, like you see it on the web.  Which is why my heart sank a little when I realized that I've only made it through 148 posts and still have 499 to go (fewer until I get to wherever I ended up when I tried to read the blog through from the other end).

As to the pace of posting, well, that did drop off a bit, didn't it?  Posts from 23 Aug 2007 to 21 Jul 2010: 500, or about one every two days.  Posts from 22 Jul 2010 to 14 Dec 2015: 147, or about one every 13 days.  So basically once every two days vs. once every two weeks.  Ah, well. I still enjoy it.  I just don't do it as much. 

I still have no idea whether there will be a post 1,000 --D.H Dec 2015]

Revolution OS and thereabouts

OK, so I just watched Revolution OS (on the Roku/Netflix box, of course), which I'd been putting off out of concern it might be more propaganda than information. The opening minute or so did little to allay that, but it turned out to be a pretty good documentary, and as even-handed as you could expect from something that interviewed Open Source folks entirely. It did this by getting in touch with several of the principals, including rms, esr and Linus, and pretty much just letting them talk. This is often a good idea, especially when the principals involved are thoughtful, creative, articulate and intellectually curious.

What emerged was a clear picture of the history of Free Software/Open Source, how "Open Source" came to be the dominant name, and the essential differences between the two: Free Software advocates want all software to be free because it's a Good Thing. Open Source advocates want particular software to be open because it's a Useful Thing. It may not surprise the attentive reader that I tilt toward the latter.

There are ironies along the way, for example a small one in Netscape adopting Open Source not through grassroots activism by engineers -- though this did occur -- but because it was eventually imposed from the top down by management; a large one in that the entire Open Source movement, which is at best indifferent to rms' s central goal of making all software free, depends crucially on GNU code and even more crucially on the GPL [more precisely: on the GPL and licenses directly influenced by it]. Rms himself points this out in his acceptance of the Linus Torvalds award at the 1999 Linux world. Linus's daughters trot back and forth behind him on stage all the while.

If you're looking for a spirited debate over Open Source vs. not-open, you won't find it -- except for an early quote from Bill Gates (who did not directly participate), there are no dissenting voices. If you're looking for knock-down, drag-out Linux vs. Windows, as the marketing collateral implies, you won't find that either. And a good thing. Revolution OS is a much more a chance to put a human face on the names you see floating around and get an idea of what they were thinking. Considered from that point of view, it succeeds nicely.


But I didn't really set out to write a movie review here. I really just wanted to share something amusing I ran across while chasing a link from a link from a page I looked up out of curiosity after watching the movie. This is from Jamie Zawinski, who has done more Open Source development than most of us, I would wager. Zawinski says:

But now I've taken my leave of that whole sick, navel-gazing mess we called the software industry. Now I'm in a more honest line of work: now I sell beer.

Specifically, I own the DNA Lounge nightclub in San Francisco. However, it takes quite a lot of software to keep the place running, because we do audio and video webcasts twenty-four hours a day, and because the club contains a number of anonymous internet kiosks. So all that code is also available.

This all sounds fine and noble, and I like the design decisions, but I have to wonder: Just how anonymous can an internet kiosk be in a nightclub full of webcams? Checking sports scores without having to establish an account anywhere? Sure. Plotting world domination? Maybe not so much.

By the way, this turns out to be post number 300. I made a production of 100 and 200, but from here on out I probably won't until some more significant milestone. Hmm ... 100π is about 314 ...

Happy birthday, Field Notes!

Well now.

A year ago I wrote the first post on this blog, about e-tickets and copy protection. The thesis, which I still buy, is that strong copy protection only exists in the physical world and that in most cases tying virtual content to the physical world is likely to fail. If technology is inherently limited but we still want people who create content to get paid, it'll be up to " a web (if you will) of legal and social constructs". The good news is that that's already how the world works.

It might seem a random place to start, but it does introduce one of the main themes here: the interaction between technology and society. I've since come to think that the web is one of the clearest and most pervasive examples of this interplay. One of the beauties of blogging is seeing such themes develop over time. You can only set out so much at the beginning. The rest you discover, thus the subtitle: "figuring out the web as I go along."

When I first started, I was imagining a wide-ranging discussion of high-level architectural concepts, spiced with real-world examples. But I kept the title deliberately vague (the original candidate, wisely discarded, was "morphisms") to allow some wiggle room. In the event, I think the focus has drifted toward a wide-ranging collection of real-world examples, spiced with the occasional comment on architecture.

I'm happy with that, and it seems more in keeping with the idea of "field notes". As I understand it, real field work in science consists mostly of meticulous observation, with theory providing some hints as to what to look for. I'm coming from the same angle here, minus the "meticulous" part. Sometimes I'll write up something I've been stewing over for a while, but if I see something random and interesting float by in the meantime I'll go ahead and write it up. Why not? It's fun.

I read somewhere that of the millions of blogs out there, most don't survive their first year, so I'm happy to have made it this far. Except for an initial burst of activity tapering off last September, I seem to be managing a dozen or so posts a month, though not at the steady rate of one every two or three days that that might suggest. This seems about right. There's always something to write about when your topic is "the web", but not always time to write.

If you've been reading along so far, thanks, and I hope you've enjoyed it. Thoughtful comments and questions are always welcome, but lurking silently is just fine, too.

Again, just what is this "web" thing?

This is post number 200, so the Eubie Blake comment goes double. Before returning to my usual random potshots, I wanted to step back and take another run at the Central Question: What is the web?

In an early post, I stumbled on a working definition I still like: The web is all the resources accessible on the net, whatever resources are and whatever the net is. That's fine as a technical definition, but it needs sauce.

Here are two ways to look at the web: the human point of view and the computer point of view.

The human view has a human shape. I'm blogging on blogger.com. I can check my local weather on weather.com, or at one of my local TV stations, generally using their familiar call letters. Companies have their own chunks of the web, as do governments of all sizes, schools and so forth. It's not hard for an individual to have a web presence and many of us do.

In fact, let's expand that a bit. I was originally equating "chunk of the web" with "domain name", and to some extent that's true for organizations. But for people, it's not. I have a blog here, but I also have accounts all over the place, some off on their own and some connected to other people's accounts. None of this requires me to have a personal domain name. Instead, I get small pieces of other domains.

This is not news, of course. Social networking is all about reflecting human relationships on the web, and the notion of personal datastores is all about letting people manage how their presence diffuses into the web at large. The larger point is that the web, having grown organically through the contributions of millions of people, is structured according to the whims of, and on a good day for the convenience of, people

From a computer's point of view, the web is a fairly strange place, compared to, say, a relational database. There is no single format for a web page, beyond broad statements like "It's often XHTML." Gleaning any more meaningful structure is a hit-or-miss affair. There are various efforts, like microformats, to make web pages more easily digestible, for example by providing ways of saying "this is a date" or "this is a physical location," but there is no requirement for anyone to use them.

There are links between resources, but there may or may not be a clear way to figure out what those links mean (is this a link to another post, or to the author's profile, or to something else entirely?). In many cases the cues are in the text on the page, or in the visual structure, both of which the wise application will generally not even try to understand.

If there's more, it's because the author of the page explicitly put it there in computer-digestible form (generally XML), or used tools that did, and because the application trying to make sense of the page has some knowledge of what the author or tool did. Either that, or someone painstakingly figured out what tags such and such a page happens to use and told an application how to "scrape" it -- until the webmaster at the other end decides to tweak the format in an unexpected way.

That's not to say that the web is completely opaque from the computer view. There has been a lot of work in this direction, under such headings as "Semantic Web" and "Web Services". As I understand it and in very broad terms, the Semantic Web is about making the web in general more accessible to computers, including (but not limited to) making human-visible structure more computer-visible. Web Services are more about creating a parallel universe of resources aimed specifically at computers, using the same formats and protocols as the human-visible web, but structuring things much more precisely so that an application accessing a resource knows exactly what to look for where.

Even in the most automated case, say when you want to use some sort of tool to book a flight, and that tool communicates directly with the various airlines and travel sites, speaking protocols that only computers were meant to understand, the human structure still wins. The connection between your tool and the travel sites, and the protocols they use to talk to each other, all reflect the fact that people want to fly and airlines want to sell them tickets.

Which brings me back to the question in the title. Another of the many possible answers to "What is the web?" is "a reflection of human society and its interconnections in electronic form."

In keeping with the "field notes" theme, here's a possible analog from biology. The class nematoda is one of the most successful on earth. If you could remove all matter on earth except for the nematodes, you could still make out most of what went on on the surface -- the topography, the shapes of buildings and roads, the shapes of larger life forms like trees and people.

Just so, if you could somehow remove all information on earth except for the web, you could still make out much of what goes on in human life. Maybe not as great a proportion as with the nematode example, but quite a bit nonetheless.

100 and (I hope) counting

According to the "Blog archive" heading, this will be my 100th post to this blog. Stephen Jay Gould took a similar opportunity to tell us, finally, about his field work on Bahamian land snails. I'm more with Eubie Blake, who celebrated a 100th birthday and who said "If I'd known I was going to live this long, I would have taken better care of myself."

I won't be writing about my equivalent of Bahamian land snails -- I wish I had something so interesting to draw on -- but on something more apropos of Eubie Blake. Blake, as it turns out, really only lived to be 96 (most of us should be so lucky), and that seems as good a point as any to pick up a thread that's been running through this blog more or less from the beginning: imperfection.

When electronic computers first entered the popular consciousness sometime after World War II, their defining property was perfection. If the hero needed the answer to an intractable problem, the computer was always there, ticking away impassively. On the darker side, the flawless, emotionless and relentless android, aware of its own perfection and our human inferiority, was a stock villain.

The computer was the ultimate in modernism. Its rise coincides, perhaps not coincidentally, with the shift from modernism to whatever we're in now, variously postmodernism or late modernism, depending on whether you want to emphasize change (how modern) or continuity.

The notion of the all-knowing perfect computer dissolves rapidly on contact with actual computers. One of my early experiences in computing was meeting my dad's friend Herb Harris, who ran a computing facility in the building . I vaguely recall watching cards being punched and read, but I definitely recall suggesting that you could use a computer to store everything in the encyclopedia (and therefore, all of human knowledge).

Herb loaned me a book I still have, somewhere, on programming the IBM 360. He also gently prodded me to consider what putting an encyclopedia in a computer would mean, particularly the question of how you would find the information once you got it there. To give you an idea of the hardware of the time, the book contained a recipe for doing decimal multiplication by use of a multiplication table you could read in from external storage. I concluded that the problem was harder than it looked, but still ought to be at least partially solvable, with somewhat better hardware. Maybe I'd get back to it later ...

Now we have vast collections of textual material available via computer, and we have at least one usable way of finding the information that's there. We even have encyclopedias on line. All this information, its storage and its retrieval deal intimately in imperfection. Some examples:

• Dangling links are explicitly allowed in the web. This is not an accident but a basic tenet of web architecture. Allowing links to point to nothing means that you don't have to build a whole site at once, or even know that it will ever get built. Among other things, dangling links are a key part of the wiki editing experience (not as much fun if you just want the information, though).
• The underlying protocols the web is built on assume that messages routinely get dropped or duplicated in transit (TCP), that the information you are looking for may in fact be somewhere else (HTTP), or that the server you're ultimately trying to reach may be down (HTTP again).
• Documents are given logical addresses, not physical addresses, on the assumption that information may be physically moved, without notice, at any time. For that matter, computers themselves also generally go by logical names. There is no one perfect physical realization of the web.
• The web inherently doesn't assume that any given document is the last word on a given subject. Search engines generally give you some idea of how well-connected a page is, but this can change over time and in any case it's only a hint. Anyone can comment on a page and incorporate that page by reference.
• You can't take anything on the web at face value, or at least you shouldn't invest too much faith in a page without considering where it came from (which you don't always know) and how well it jibes with other sources of information. This sort of on-the-fly evaluation quickly becomes a reflex.
• From a purely graphical point of view, there is no definitive format for a given web page. If you try to lock everything down to the last pixel it will generally look bad on displays you didn't have in mind. If you don't, it's up to the browser at the other end to decide what it looks like, and with CSS and other tools, the viewer can have almost unlimited leeway. Nothing is perfect for everyone, so we try to get close and allow for tweaks after the fact.
• A key part of running a successful web site is managing details like backup, maintaining uptime in the face of hardware failures and (one hopes) dealing gracefully with large numbers of people pushing the limits of your bandwidth. This is hard enough that you generally want to farm it out.

There are many more examples, and probably much better ones as well. The point here is that even when it looks like the system is working just fine, imperfection is everywhere. The web tolerates this rather than trying to stamp out every last flaw, and in some fundamental ways even builds on imperfection. The result is far more powerful and useful than a computer that never loses at chess or never makes an arithmetical error.


Postscript: Herb Harris is no longer with us, but the University of Kansas student computing lab bears his name [... or it did for a while.  Somewhere around 2010 the trail seems to go cold.  Now that everyone has a phone or laptop and storage is in the cloud, there's no longer such a need to go to a place in order to compute.  The building is still there, but it now houses "Information Technology".  Sic transit ...  -- D.H. Dec 2018]