Sean McGrath has written an entertaining, enlightening piece, musing about the economic arguments for microformats. Go read Master Foo’s Taxation Theory of Microformats, but first, a preview:
“History has shown that the only way to reduce information processing complexity to zero is for applications on the value chain to have build-it knowledge of the information formats they work with. XML, RDF, UML and so on are not formats so much as meta-formats. Consequently, built-in knowledge of any of these does not amount to zero complexity. XML is not a file format. It is a file format for file formats. This distinction is all important when calculating complexity.