Yahoo answers is pretty good to get targeted traffic, basically, you build up an account upfront and give a few answers right and left on this you know and it's not hard to find questions that you can answer. as your level goes up, you have more possibilities. Anyway, you can ask someone to post a question based on products or services you sell and you answer it posting a link that help (or so) and get 3/4 people to plus your answer, it will rank pretty well soon and you ll get some cool traffic. But watchout, Yahoo is looking around.
Spamming in yahoo answers is a treason you will get banned. The best way to market you than market your website because market you will automatically market your website.
it does, though don't expect thousands of visitors in short time, but it does bring traffic over long term