Yeah. Definitely yahoo ll give you good traffic, if you submitted your site on right category, It will let people find you site there.
Absolutely spot on, I've been saying it for ages. I think $300 I spent on Yahoo Dir was the best spent $300. But well, if your target is to make a few bucks a month from a website than yahoo dir is not for you. For any other websites yahoo is a place to start with. You have to remember that even google ranks yahoo listed websites higher as junk and spam webmasters don't have $300 (and then there's manual review as well) and thus mainly authority and good websites listed in yahoo directory. Thus, if you're serious about your website and plan to make it profitable then yahoo directory is a great place to start with.