As you know I have quite a bit of interest in Question and Answer sites. This new research coming out of the University of Minnesota caught my attention: U of M study finds you get what you pay for with online Q & A sites
Surprisingly the Web site Yahoo! Answers, which provides answers for free, performed as well as Google Answers when the fee was low ($3) and outperformed reference librarians and an "ask-an-expert" site. Researchers attributed this success to the large online community that contributes to that site's answers.
If you can sift through the noise on Yahoo Answers you can find some good information. I find it interesting that the most successful site, if you paid enough money, was the discontinued Google Answers (which lives on at Uclue). Seems to me that the take-away from this research is that unless you're paying people pretty well to do some in-depth research to answer a question, the next best thing is to make sure that lots of people are involved in vetting the answers.