Yedda, an Israelian startup is a service resembling Yahoo Answers. You can ask your questions and everyone can respond to them, sharing knowledge about the subject. As Yedda says :

We are building Yedda as a fun place to share, explore and discover knowledge - a place where you can connect with people having specialized knowledge or with people of interests similar to yours.

Although several people asked on Yedda why and how Yedda is different from Yahoo Answers, no answer has been posted to this question. And frankly, I don't see the added value either. Yes it is a nice site with a lot of features, but technically you can do the same on Yahoo Answers. As we dutch people say : "thirteen in a dozen", meaning plenty of others did it before you.
If you think otherwise, do not hesitate to place a comment.