Apparently, "folksonomy" is at the top, and I've never heard of that word. Suupposedly tagging is a form of folksonomy; according to Urban Dictionary, it refers to the spontaneous categorization of info by a non-hierarchical group of people.

But the second and third entries, "blogosphere" and "blog" are totally warranted. It's "weblog", not "blog". So ha.

(via ArsTechnica)