Rediff launched Rediff Q&A in beta few days ago as reported on Pulse 2.0 and it is all copied interface and the logic of Yahoo Answers. Here people ask questions and at the same time they can answer the questions asked by others.
Rediff Q&A is a platform designed to address a need. Every day, our mailboxes are filled with reader queries on all manner of subjects; clearly there is a demand for information. Rediff Q&A provides a platform where you can ask the questions you need answers to, get answers from your peers, and also provide answers to others who may be in need of help.
There is point system in place which provides points to the users on the basis of feedback given by them. On the basis of points accumulated, users are provided higher privileges.
Just on the lines of Yahoo Answers, there is voting system to vote for the best answers. There is hall of fame section for top scorers of each week.