What’s a microformat? Jesus, good luck figuring out from microformats.org. That’s the most useless description of a technology I’ve ever seen.
What is a microformat really? It’s a way of embedding structural information in the id and class attributes of xhtml to map back to an arbitrary xml standard. For example, you can embed vcard in xhtml with hcard. The advantages are twofold. One, the material is then viewable with a stock browser (styleable with css). Second, it can be embedded in other standards like atom that have specific profiles for embedding xhtml.