yea they are no follow, but it is a decent way to generate some traffic. It is a little time consuming, but while doing you can actually learn quite a bit so it keeps it interesting. Tip: generate even more traffic by creating two accounts and answering your own questions with good answers and a link to your site. (but dont be too obvious about it)
Yahoo! answers are nofollow, if they see it as spamming, your site will be banned from Yahoo! Search Engine also and your Yahoo! Answers account will be disabled !
It means they add nothing to sites rank in search engine. They give no page rank for being on the site.
I agree with you.Recently, i have just posted several questions in yahoo answers and they then appear in google search , i do think this will help you to generalize your website.
if you wont get your site banned, they will block your answers that contain your domain name, so you wont be able to post it there dont spam the site, use nice answers