"Microformats are open data formats that some Yahoo! sites support. You can't see them (unless you do a "view source" on a web page), but they're there -- bits of HTML that describe things like contact information (hcard), a review (hreview), an event (hcalendar), or a listing (hlisting). Microformats make data in web pages reuseable since the data is in a standard, canonical, format instead of just a jumble of HTML. Thousands of sites expose their data in Microformats, and that data is available for developers to use. One of the best opportunities for developers to make use of Microformats is in the forthcoming Firefox 3 web browser which features a new global Microformats object and API. The new API makes finding and parsing Microformats trivial and efficient..."