Awhile back, I complained that I couldn’t find a clear, straightforward, non-technical explanation of RSS. Well, here’s a good one from Michael Fagan. For a more technical introduction to RSS, see Mark Pilgrim’s explanation.
Fagan’s site, incidentally, has a handy general search page that lets you target a couple dozen online search engines and information resources from a single search field, plus a blog search that targets weblogs and RSS feeds.