Posting on Yahoo Answers can beef up your backlinks if nothing else. I've posted a few answers within the last week and they were all indexed in 1-2 days. If you do intend to post on Yahoo Answers, make sure you don't use the same link for every answer...i've heard of accounts getting suspended for it.
I've found that Yahoo Answers CAN provide some quality targeted traffic when used correctly. There is a good eBook called "Leveraging Yahoo Answers For Cash" which is 101 pages long but has some really good info. PM me if you want to buy a copy!
I dont think to get more traffic by yahoo link . Better try for another web marketing technic like forum posting, blogs , directories etc..
I advice you to spend your precious time somewhere else rather than answering the yahoo answers as it will not give anything worthy for your site. I tell this from my personal experience, as the older answers are just deleted from the servers to save space and if at all they are present, they are just no follow links. Think twice before you leap (answer)
I never considered Yahoo Answers a good place to market your site. Lots of people get suspended and all plus nobody's really going to care clicking on your link if your answer's over a few months old. Frankly, it's simply not worth the time and effort.
Yes guys Yahoo answers does infact increase your backlinks. It helps Yahoo SERPS a lot for your keyword.