I'll take StackExchange over Yahoo Answers for technical topics (where YA is mainly populated by kids posting their homework and spammers advertising tutorial sites unrelated to the question), but YA has been effective for getting information on popular opinion (e.g. what people think are good restaurants where I'm going), expectations in social situations I'm rarely in (e.g. how to properly tip a bartender), etc.

In both cases, it's nice that I'm never the first to want a particular question answered.