You can get your craiglist ad listed in the search engines for a very short period but if thousands search that term you will receive a lot of traffic. Both can be a useful short term traffic fix
Yahoo answers get you some targeted visitor but they are nofollow links, CL is also targeted visitors but the links last very little.
Yahoo Answers definitely works for traffic but as stated, they are nofollow so don't count on them for any backlinks. Still, it's a great way to generate targeted traffic quickly, at no cost. I haven't tried Craigs List, (been stubborn about that), but I've heard from many people how effective it can be if you structure your posts correctly.
Yahoo answers is a nofollow, but I've gotten great traffic in the past for some of my product reviews after others added the review as a resource.
For traffic yes you can expect because google crawl them easily and give good ranks as well. But since they are no follow so no benefit for link building.
They are perfect if you want instant and targeted traffic. Not a popular option for link building strategies.
wow, didnt know that yahoo answers have nofollow policy. but, yeah from my own experience, i tell you the yahoo answers is a great source for increasing traffic.
one of my client has a consulting website so its effective for him . On the other hand its not so effective for a person with pure business website . It depends what you are promoting