I've been addicted to Yahoo Answers lately, because it's fun to give people advice, but it's also sort of depressing. For all the legitimate questions posted there, there are just as many that are either:
2) Lazy - posted by students looking for someone to give them as much help with whatever school paper they're working on. Two examples here and here.
3) Shilling for some company (and, hey, I've done it too, but only on topic.)
4) Even more asinine.
5) Or both 3 and 4. Example.
These are all just from the movie questions section. If you search around Yahoo Answers in general, you'll get a similar cross-section, of useful and depressingly useless.
Still, I enjoy being the first to help someone figure out which movie they're thinking of, so I can't help check that site, but boy, it's depressing. And that's not counting the spelling challenged among us, too.