Don't waste your time on Yahoo answers. Ocassionally dropping your link is fine but you wont get much from it
Just check your logs man... it shouldn't be too difficult to spot their referring url if there's any ..
I've done this for getting targeted traffic. It's an excellent way to get people who are looking for answers and you provide them a solution (website). Great for marketing.
I think you would be able to get some traffic from Yahoo! Answers but it appears they have NOFOLLOW, but I think it's still worth the traffic you get from them.
If you take it serious, and try to help askers, you will get some traffic and clients. They do have no follow tags Thanks