In its classic game-theoretic formulation by David Lewis, a language is defined formally but established and used according to convention. A convention is used by a community to solve some co-ordination problem, such as determining how to list dates so as to schedule meetings or record history, even if such a choice is arbitrary (the American convention of listing the month before the day as opposed to the European method of listing the day before the month). The identity and meaning of data on the Web could be viewed as a co-ordination problem. A further general idea that falls out of a game-theoretic analysis is that people will in general use the minimum amount of convention to solve their co-ordination problem. This rule-of-thumb might explain the slowness of the Web community to embrace model-theoretic semantics.
I was in the audience at Harry’s IRW2006 talk, and that little gem stuck with me. The Semantic Web (and the web in general) is a co-ordination problem among a large number of publishers and consumers of information that do minimal communication with each other.
“Building the Semantic Web,” then, means to me, “Identifying a minimal set of practices that enable large-scale interoperability of RDF data.”