More social classification

Jon Udell nicely articulates the value of social classification (a point I made in my folksonomy post):

But the tagging disciplines in del.icio.us, and also in Flickr, are far more accessible. Although conventional wisdom says that people can't be bothered to assign metadata tags, users of these systems do -- partly for their own benefit, and partly because the collaborative result is more than the sum of the individual efforts.

And Stewart Butterfield describes why it works (emphasis mine):

I think the lack of hierarchy, synonym control and semantic precision are precisely why it works. Free typing loose associations is just a lot easier than making a decision about the degree of match to a pre-defined category (especially hierarchical ones). It's like 90% of the value of a "proper" taxonomy but 10 times simpler. (Of course, I don't know if there is a lesson there for the everyday work of IAs - different kind of problem.)

Cool. Cheap, easy, imperfect but still highly usable social classification schemes.