Interesting. The argument is that to build something that "is like facebook but..." is a poor idea and that it would be better to not build a monolithic structure. So in the end the argument is "build something that is like facebook but distributed" :)
Honestly, it looks like what he is trying to say is that even a distributed facebook is not ideal. What I get from this is he wants to "Build something entirely unlike Facebook" using an interface and medium that are not a website.