You bet I do. I use it to answer questions and I've also gotten traffic just from people recommending my sites in their answers. So far I've receved over 30 visits this month from Yahoo Answers to my fitness site. Not a lot of traffic but I'll take it considering it's all free, word of mouth visitors.
I know people who go there at least once a day to answer various questions in their niche, which is a very good strategy if you ask me. Especially if you take your time to craft helpful, useful answers.
Any little bit of traffic helps.