I find YA good for two things, targeted traffic and testing your knowledge Only answer questions related to your website - this shouldn't be a problem as this is your business if you don't know enough to answer a few questions then you got a bit of work to do. The problem is there are YA Trolls people who don't have website and just like to comment on everything. My personal fav at the moment is in any question related to home business or internet marketing she post "CNN reports 99% of all home based business are scams" over and over. I actually got a warning for reporting this post as spam as it was in Yahoo's terms relavent to the subject matter. It would seem the higher your standing within the YA system the more you can get away with. (within reason)
Right. Yahoo Answers is strict with link dropping. They will delete your post and you have to appeal for inclusion of your post. Make sure that when you post a link, it is relevant to the subject.
Yes yahoo answers is good in gaining traffic to your site just find a related category with your sites then answer correctly and place your site into the resource page.
I have L2 as well and added some links, but according to Awstats there is no traffic from answers.yahoo but they are logged in Google Analytics, so it generated some traffic.