Does Metcalfe's Law Contradict Data Portability?

I’ve been on a bit of a data portability binge over the past few days. I wasn’t going to write anything more about it until I came across Andrew Chen’s post arguing that Metcalfe’s law is “a DIRECT reason why these networks want to get as big as possible, and have a social graph that’s as comprehensive as possible, and why they should ultimately be opposed to Data Portability.”