Yahoo Answers can be a significant marketing tool. Many bloggers will post relevant links to their articles from their Yahoo Answers without breaking any rules. Starting July 1st 2009, Yahoo decided to limit linking for new level one Yahoo Answers account. A level one Yahoo Answers account-owner can post URLs in their answers, but they won’t be links people can click on to visit the destination URL. Once a Yahoo account reaches level two, the account owner can post links in their answers.

Are Yahoo Answers backlinks good for SEO

The answer is no, in the sense that the Yahoo Answer links are 'no follow' links and don't transfer any PR(Page Rank). Posting relevant informative links in your Yahoo Answers and providing good answers will still generate targeted website traffic. There is a chance that Google may change their minds in the future. Google does give relevance for natural seeming web content and links, so it's a good idea to have some nofollow backlinks just to appear natural.