Then you have the whole adversarial network aspect. People will intentionally pollute the category system for purposes of advertising, propaganda, jokes, etc. G

Then you have the whole adversarial network aspect. People will intentionally pollute the category system for purposes of advertising, propaganda, jokes, etc. Google bombing is basically a kind of semantic hijacking that happens already and we don't even have a semantic web. The test for any proposed Internet standard or system should be "what happens when 4chan hears about it?" I don't see semantic web ideas taking off outside of closed forums and walled gardens like academic research or the military. On the public Internet you'll rapidly end up with Donald Trump mapping to "small penis," etc.