... I don't think that any semantic web skeptic, and I have been one, has ever disputed the value that can emerge when you traverse RDF-style data sets. The question has always been: How will we get people to create those data sets, in ways and for purposes meaningful to them? The Simile team are laser-focused on solving that problem, and from what I can see they're biting off huge chunks of it with these tools and methods.
I'm not suggesting that ontologies will play no role, but I've long believed that we need to evolve toward them from real data that people can create, use interactively, and begin to cross-combine. That's exactly the approach that Simile is taking. Seeing it in action, and then easily reproducing it myself, totally made my day.