Flickr does tags better than any other, so far as I can tell.
We love tag folksonomies for way they allow us all to organize our world, for the way they allow patterns to emerge from chaos, and for their easy flexibility. But that flexibility, if poorly implemented in our software, can interrupt the very patterns we hope to find in our tag networks.
Take “road trip” as an example. What one tagger thinks is two words might be just “roadtrip” to another. This is where Flickr’s tag indexing does it right: we still have to pick the right words (and spelling), but we don’t have to worry about spaces or punctuation.
So, when I tag a photo “Mt. Moosilauke,” Flickr stores the both text I enter as well as a version in all lower-case, without spaces or punctuation: “mtmoosilauke.” And when you search for “Mt. Moosilauke,” you get the same results as your neighbor searching for “mt moosilauke.”
Well, that’s how I think tags should work, anyway. And you’ll notice it’s how they’re working here now. The text of the tags at the bottom of this post and all others here displays as I entered it, but they resolve to a tag URL without spaces or punctuation, just as Flickr’s do.
Um…update: okay, Matty and I agree and disagree about a few things, but he just re-wrote the core-tagging function in bsuite, so I’ve gotta give him his way on a thing or two for a moment. So…tags are back to the broken Technorati standards. That is, somebody searching for “roadtrip” won’t find posts tagged “road trip,” but we’ll fix that in time.