There are a few ways now that you can setup RSS feeds to recognize an affiliate webmaster's ID. Basically, you're doing a hosted "post", complete with either pictures, or a movie clip, and sexy sales text.

Blog software (Wordpress) and programs like Movable Type, Joomla, Drupal, etc are able to create an .xml file that consists of all of your posts. RSS stands for Really Simple Syndication. When you go to some sites, and see those latest news updates on the side or possibly the latest stock market prices ... the site is using an RSS feed to bring in that information. Everytime new "posts" are available from the provider of the feed, your site updates. In the same manner, everytime you update your member site posts you rss feed also updates. The new post will now show up on all of your affiliate's blogs who are bringing in your Rss Feed, automatically updating their site.

You can use a program like CCBtools.com, the feed service script from the Mojfun.com site, Nats has one built in (that I never did figure out), or purchase Blogs Oranizer along with the affiliate module to run a whole mess of blogs, either ones for affiliate use, and/or your own blog empire from one control panel. There's another plugin one for wordpress I think, if I track it down, I'll put up a link.