These semi-pseudonymous networks have strong enough network effects to fend off the competition because they’ve given their users a persistent online identity to which they commit. As social creatures, people are emotionally invested in creating, building, and maintaining their reputations — even if that reputation is semi-virtual.

It wasn’t that network effects and Metcalfe’s Law were wrong, it was just that they didn’t capture the reasons that someone might use a social network beyond pure utility, so Wei proposed a new framework for analyzing social networks’ strength that added social capital to the mix.