The best blog post I read today was on TechCrunch, written by Naval Ravikant, an early investor in Twitter, and Adam Rifkin, who I once knew, a long time ago, when he was starting a wonderfully-named company called KnowNow.
I wrote poetry about the name of the company, here on Scripting News.
Neither of them has a language for defining relationships, in other words I can't extend the idea of a relationship arbitrarily. And it doesn't seem to be in the DNA of either company to allow others to get in there and mess with this core stuff. (When Twitter started they made it seem like it was their philosophy, but they've been pulling back from that, in some dramatic ways.)
No doubt we'll look back at these networks years from now and see them as starting points, because neither now has anything like the full richness of human connection that can be modeled in computers. And of course some relationships will be very difficult to model in a computer's memory. But for now and for the forseeable future, there's lots of growth possible in this form of modeling. Maybe that's why there's so much investment today in tech.