You can read the official blog post here.
In a nut shell, upon giving Yedda your twitter username and password, you will be able to share your Yedda expecrience with your Twitter friends.
We will twitt on behalf of you about questions you ask, answers you give, questions you add to your watch list, thumbs up you give to other answers and questions you are being invited to answer by Yedda (all configurable through the settings screen).
Share the Yedda love through Twitter. It’s fun! (and I’m not just saying that because I am a part of Yedda ;-) really!)
Just beware: it’s addictive.