Just launched in beta, Yahoo! Answers is a place where you can ask questions on any topic and get answers from real people. It's free, presumably funded by sponsored ads. Keen.com started out trying to provide something like that, and it's still around as a sort of psychic/astrology advice line, but clearly Yahoo has bigger ambitions. The big question on these Power of Us services is whether the incentives--in this case, it appears, the chance to build a reputation from people's ratings of answers--will be enough to build a critical mass of users. As soon as I can check it out, I'll post a short update.
UPDATE: Looks like Yahoo folks or alpha users or both seeded the questions to start--everything from "What's the best John Coltrane album?" to "Just took poison what should I do?" (don't know whether to laugh at that one) to arcana like "What is the max speed cpu an FIC KA-6100 motherboard can support?" (Yes, someone answered that.) Categories are a bit limiting for now, and you have to register to post a question, but it's pretty easy to use otherwise. I've asked my own question and will see if anyone has the answer.
Pete Cashmore at Mashable offers some interesting thoughts and links that point out that people should view the answers they get in open forums like this--even those with reputation systems like this one--with caution. Gary Price also takes a detailed look, as well as a look at the alternatives.