wikianswers.com amazon has an answers site i think but forget what it is called mylot is kind of like it too, except its more discussion than question based but has the same rate answers type of thing. if i think of more i will post them!
Yeah I agree with what people above said, I was going to say that forums are basically question and answer. If you are looking for a place to spam than Yahoo Answers is probably the most relaxed out of them in terms of moderation, but if you want quality traffic I would suggest giving good relevant answers on forums.
Thanks for your feedback. found it.. http://askville.amazon.com While you and others mentioning forums are correct I feel that Q&A sites may get the message out to a different type of audience. Besides I find the concept of a Q&A site interesting. Here's a couple others I found while looking around today. http://www.answerbag.com http://qna.live.com http://www.blurtit.com/
Here are a couples of sites that I know : http://www.wikianswers.com/ http://www.funadvice.com/ www.allexperts.com www.ansmart.com www.ask.metafilter.com www.wondir.com www.askville.com www.yedda.com
I want to build a website like yahoo answer, maybe it can get traffic very easy. but how to make money? just adsense?
The only hurdle is getting users to post questions and others to answer. This comes with credibility and marketing.
I would like to contribute too. So, Q&A sites that haven't been yet mentioned: http://nownow.com/nownow/ http://iq.lycos.co.uk/ http://qna.live.com/ http://www.linkedin.com/answers http://www.fluther.com/ http://wis.dm/ http://www.answerbag.com/ http://www.knowbrainers.com/ http://www.theanswerbank.co.uk/ http://www.loc.gov/rr/askalib/ I hope it will come in handy