I read a few comments here, and I'll disagree a little. Yahoo Answers don't ban you without any reason. Yes! You can't spam the site. But, if your answers are credible and rewarded as the best answers often, you won't have any problem. Though, I don't use Yahoo Answers now, but I'd more than 30% best answers there. I of course spent some time in finding and creating those answers, but believe it or not, after less than 500 answers (including the best answers) I guess, I was receiving 150+ daily visitors, even after a whole year - without touching Yahoo Answers. So, it works. And, they won't ban you either without any reason. Just focus on receiving the best answer trophy, and keep the ratio good as well, and I'm sure the links you post in your answers won't matter.
I agree that quality answers are key, and providing something of value that is useful to the reader. Even in doing so, it is still possible to get banned depending on how strictly Yahoo Answers enforces its TOS.
Choose relevent question to your website content and answers those in a good way so that people could be interested reading your answer. You can put your website's link in your answer or source and you can get a good amount of traffic from there.