I'd have to disagree with anyone who thinks the Yahoo directory languishes without much use.
Last week we put together a site and submitted it to Yahoo. It was approved late yesterday and published overnight.
This may not be "huge" traffic but I was shocked to pull up the logs and find that we had 130 Yahoo referred visitors by noon (EST). They were from all over. One visitor even added the link to his blog and we'd recieved 4 visitor referrals from that link (probably all from him).
By noon we'd been crawled by googlebot, scooter, alexa, jeeves, and a few unknowns.
This is for a domain I only registered 2 weeks ago.