Forget about Yahoo Answers try Quora, may be too early to say but Quora is continually improving collection of questions and answers site, aggregates question and answers to many topics and allows users to collaborate on them.
In Quora when someone comes up with a question, others can provides valuable answers the best answer reaches top of the page. Quora users can comment on the answers to make them better as well.
Each question has set of topics attached makes it easier to find questions on Quora site. The topics also used to identify related questions and sometimes give context to a question.
Though Quora is open to public, yet you needed to be invited by someone using Quora to access Quora. If you are Quora user, don’t know how to invite your friends to Quora, here is how.
Inviting people to Quora
1. Sign into Quora website with email address and password,
2. Visit http://www.quora.com/contacts page in your browser, on the right side of the page you will Invite people by Email dialog box, you can enter email address of the person you want to invite to Quora under “Enter Email address” and click the “Send” button.