Microformats
If you’re trying to get your head around microformats, this microformats primer from Digital Web Magazine is a decent place to start. The philosophy-to-applicability ratio is still pretty high but it’s among the better of articles I’ve come across. If I understand it correctly, the idea can be boiled down thusly: microformats are a way to communicate structured data through Web pages and other vehicles that were traditionally used to translate display-oriented markup.