We Need More Alternatives to Facebook.

(…) having many more niche alternatives to Facebook could be exactly what we need. Even if none stole a significant chunk of Facebook’s users, it might be enough to remind people that even as Facebook becomes more powerful than ever—rolling up massive profits and preparing to beam down Internet access to offline corners of the globe—other options are possible, and vital.

Relevant: Solid (derived from "social linked data") is a proposed set of conventions and tools for building decentralized Web applications based on Linked Data principles.