Now that I've tagged it, how do I find it?

I try to assign a few relevant tags to every post, as is common practice. Blogger's tagging facility (along with lots of others, I expect) will suggest tags you've previously used. For example, if I type "bl" into the space, up comes a list containing blacksmithing, BLOBs, blogger, blogs and Eubie Blake. Hmm ... I'd forgotten I'd used "blogger" as a tag before. Curiously, J and only J, pulls up only personal names. I've been known on occasion to run through the entire alphabet to make sure I haven't missed anything.

Conversely, if nothing pops up for a tag, you know you haven't used it. That happened for DMCA on the previous post. That's funny. I'm sure I've mentioned the DMCA before. Aha, there are a couple. All I have to do is search. A couple of quick edits and they're tagged now, too.

Now, if anyone could find those by searching, why add the tag? Indeed, I almost didn't add the tag, because those posts don't happen to be about DMCA. They mostly just mention it in passing. I opted to tag those because the passing mention was apropos of what DMCA is. On the other hand, this post contains the letters "DMCA" but has nothing to do with it.

Likewise, there are a couple of posts, like this one or maybe even this one, that don't mention DMCA specifically, but might be relevant. On review, I'm not tagging those DMCA either. They're both tagged "copyrights" now.

While reviewing that I ran across another post that should have been tagged "copyrights" but wasn't. That's a recurring problem with tagging. Which tags should I use here? Which tags did I put that article under? Did I think to put it under "copyrights"?

All of this leads me to a few general points on tagging:

• It's not particularly new. It's much the same as traditional indexing. In web form, it goes back at least to categories on wikis.
  
• It's time consuming and subjective. Care and feeding of categories is an important part of wiki gardening, for example.
• It's most useful exactly where more automated tools don't work. If you want to find posts here that mention DMCA, just search. "DMCA" is probably not a particularly useful tag. "Annoyances" and "Neat hacks" make better use of the tool.
  
• Likewise, tools like sub-categories or other schemes for tags to aggregate other tags, though useful, aren't foolproof.
• On the other hand, tags are still nice for browsing, particularly the more abstract ones.

Tagging is time-consuming because it's subjective, but this is also what makes it useful and even intriguing ("why did they tag that that way?"). Automated searching remains the workhorse, and will probably continue to.