Yahoo dir is PR8 which is the second most high PR after DMOZ afaik. (yahoo's pr is 9, I'm not talking about yahoo's PR) But Google is an intelligent company, I mean, it's a paid directory. Google knows this. Will Google really award my site with higher PR when I add my site there? (Let's think that there's no backlink else) If I was Google I wouldn't count backlinks from paid directories?
Some say it's good for SEO, some don't. If you have spare money my suggestion is to add your site to yahoo dir.
Well, Google doesn't think like that. Spiders always looks respected and fresh content. If a directory has huge load of backlinks, you can count it as respected. And respected sites keep posting quality stuff. Take a look at AvivaDirectory. It is not only a directory but also freaking super blog for webmasters. To sum up, you can go for directories with content. Oh.. BTW Yahoo! is a giant network. They don't need to build content to get reputation. But don't waste your money with Yahoo! Dir. My suggestion is to go for DMOZ. It directly changes your SERP.
newyorkmarketer wrote Could you please provide us with some evidence (figures, articles, personal experience,...) of that?
Webmaster's that are listed in the Yahoo Directory have told me they only get a few visits a month from it. So as far as traffic goes I wouldn't do it for the traffic.