Now that tagging is in place and working more-or-less as we intended, there's an interesting question about when to use tags and when to use search. Specifically, I find myself wondering, is it worth tagging an entry with a keyword that you probably won't use again? Example: I reviewed Charlie & the Chocolate Factory a while ago, and I tagged it with "Charlie" and "Chocolate" and "Factory" (as well as "movie" and "review"). But do those tags accomplish anything?
I can think of three things that I (or even a reader) might want to do:-
- Find all my reviews of everything – movies, books, CDs, whatever.
- Find all my movie reviews
- Find my C&tCF review
Finding all the reviews can be done using the "review" tag. Finding movie reviews can't be done with the tags I've used – everything tagged "movie" includes bits of news, trailers and so on, as well as reviews. Everything tagged "review" includes CDs and books and games too. Luckily there's also a "movie review" entry type, so a link to that could be used instead (although I don't include those links on my blog sidebar).
Finding the C&tCF review could in theory be done with tags (eg. "Charlie"), but since those tags are used only once, they don't make it into my top twenty tags list, so they don't appear in my sidebar. The best way to find the review would be to do a search for Charlie or Chocolate or Factory, any of which return the review as the first result. (And when Chris unleashes his arctically cool Live Search on Blogs, searching will be even better, because just entering a few characters into the searchbox in the sidebar will immediately put a list of your matching entries right there in your sidebar, not on a separate page.)
So I suspect that it's not worth tagging an entry unless you're going to reuse the tag, ideally many times. And there's a trade-off between general tags like "movie" and "review" and more specific tags like "movie_review". I had imagined, without taking the time to think it through properly, that my tags would allow me to easily retrieve all my movie reviews, but I was wrong. Unless I tag things with "movie", "review" and "movie_review" then tags won't allow me to find everything I've written about movies, just my movie reviews, or all my reviews. Now that I've taken a moment to think about it, this is blatantly obvious, but the general point about choosing your granularity carefully (or using lots of tags for maximum coverage) is, I now think, not as simple as it seemed to me when I was just tagging away with whatever came into my head.