To be safe, just answer the questions with the best you can and don't drop your site link on every answer you have. Those looks spamming and you might get ban.
It's really involved a huge amount of works for any internet marketer to get their site links or to get back links to their site. Yahoo answer is one of many way you can get links to your site but again, it is involved and required your part of works. A lot of it too.
The best way to get up a level is to get the best answer. I have found this is easy if I spend a little time to think about the question. Best answer will get you ten points while just an answer will only get you two. You will save some time by answering with quality.
Anybody had success posting links on Yahoo Answers? I guess on paper it seemse like a good idea. But I know when I'm browsing around there for fun I won't click a link unless I'm pretty sure it leads to an educational site that will give insight on the answer. If I see something like an affiliate page or an Adsense Site, I tend to go away.