[Animats]

So how would you launch a decentralized social network?

You could do what Zuckerberg did. Start with big-name colleges. Call it FratNet. Get a few key fraternities and sororities on board. Each frat has their own node, but it's probably in a data center and costs like a Wordpress site. Offer it on mobile. Log in with face recognition. A key function is a good events calendar and invite system.

Then roll it out to other groups which have lots of events, such as churches.