Tags for HN?

Has there ever been discussion of a simple tagging system for HN posts? I think only moderators should be able to give a tag, there should be only one tag per post, and I would suggest just five: "Business/ Startups", "Computer Stuff", "Science and Technology", "Society and History", and "The Arts".

It is easy to over-ontologize, and a waste of time, but on the other hand, I could then ignore everything about startups and exits, and concentrate on the weirdly good social theory discussions that cross HN but often don't make the top page because of GPU and compilers and the like. (Don't get me wrong -- compilers are cool, just saying...)