In an interview with News.com, Dave Hollander on XMl and the future of data. He says the biggest problem is that of transformation:
It means, how does the receiver interpret the intent of the sender of the information? The easy one to think about is in language, going from French to German, “rue” to “strasse.” Being able to understand that intent, and transform what the sender intended to what the receiver needs to do, becomes a transformation. Semantics is understanding the intent of a thing, of a concept. I like to think of it as the boundary between data and behavior. If you send out the same data and get five different responses, then there are five different semantics associated with that data. In order to do a transformation from “rue” to “strasse,” I have to understand the fundamental transformation that this is a street, and whether it’s a street or highway or road needs to be differentiated. In order to make meaningful transformations, you have to understand the semantics of the information.