No it doesn't directly help in SERPs or traffic but if people like your answer or you quote your website in reference to any of your answer then yes, you may expect some quality traffic But as I mentioned earlier, if you unnecessarily mention your website in your response or try to spam then people may start ignoring your response even your genuine response may also go unnoticed
Yahoo answers helps in generating traffic if you use links for reference related to your site. You can manage good Yahoo profile. It helps a lot in traffic.
Its a way to build your traffic via using yahoo answering tool. Most of the individual's ask their queries via using yahoo answering forum. So someone refers them the link or the number depends on the queries.
Yahoo ans is very good to get traffic to your website .In yahoo ans you can give your link resource with your answer
It could ONLY help you get a few more visitors to your website. NOT for SEO because you should use your domain name as an anchor text! Also, it's really hard to get a quality backlink from there (from a page in Yahoo Answers that has ONLY a few answers and the topic has a good ranking in Google!)... And then to get it with a really HIGH quality post and place your website in it... And you should NOT spam!
Yahoo Answers can be really good if you become an expert in your niche. Do this by posting relevant and valuable information consistently. This is the only way it works.
Yahoo answer is used for increasing Traffic to your website . But make sure that you have to give correct Url (www.domain.com) of your site don't give (www.domain.com/#_=_/???.1php), Give exact slug, don't use special character on it .this may help you. I have personally experience it. Keep in mind while you answer any question which is very relevant to your subject
yahoo is good for traffic but facebook and google plus are best, but still the more services you use, the better the result gets