I like Clipfire , which allows users to submit ecommerce deals, and other members can vote the best deals to the top of the site, and add appropriate metadata, like tags, to the links.
Think Digg, but only for ecommerce. It’s a young site and not a lot of users are there yet. But founder Kevin Carey has a big trick up his sleave – not only does he allow user submitted links to have affiliate codes, he absolutely encourages it. So users have a big incentive to push suggest great deals on the site…they can make real money doing so.
RSS feeds for everything, of course. I like this almost as much as Woot (you do know about Woot, right?).