This is really helpful stuff. The key here is not to spam like crazy. Work your way up and get decent points then promote your site carefully.
The below steps may be useful for you:
Step 1) Become a member of Yahoo Answers, upload avatar and fill in your profile with general and accurate information.
Step 2) Pick the category most relevant to your business or site.
Step 3) Check that category daily for questions that you can answer accurately and informatively.
Step 4) Perform searches in Yahoo for your top keywords or keyphrases. Answer the questions supplied by Yahoo Answers in the normal Yahoo Search results, these will get the most web search eyes and possibly clicks on your links.
Step 5) Use the Yahoo Answers social network to make friends with every person asking or answering questions within that category. Yahoo Answers uses a one click Ajax tool for adding friends (contacts) which is very efficient.
Step 6) Answer the questions that you can and link to your site as a reference when best suited.
Link to other sites as references so your participation is not mistaken as spamming.
Step 7) If others are answering questions more accurately than you, star or vote for their answers, this is a good way to make friends.
Step 8 ) Take two or three hours a week to perform this simple yet effective social media participation, then check your log files or stats to see if this is building traffic and conversions. If it is, rinse and repeat.
Step 9) Also take into account that Yahoo Answers information will be indexed by Yahoo for a long time, this is not just a quick marketing fix. Yahoo Answers info is also integrated into Yahoo Local, Yahoo Search, Yahoo Brand Channels and other Yahoo content channels, so the audience is growing significantly.