I wrote a book proposal in 2003 that boldly announced that the Web was on the verge of a fundamental change from being a repository of documents to a source of knowledge. The Semantic Web, long discussed and theorized about, was on the verge of becoming mainstream, I wrote. The book found no publisher, and I graciously avoided the fate of so many prognosticators who find their predictions proved false (or premature) by the slow, plodding steps of history.