It could easily be distributed in a fashion similar to say bittorrent. Whatsay each node contains it's own users's data, as well as the data from several other

It could easily be distributed in a fashion similar to say bittorrent. Whatsay each node contains it's own users's data, as well as the data from several other users. When you look for someone, your node looks for the nearest node containing that person's data. Theoretically, something like this could be impervious to small scale outages. That would give it an edge even on Facebook.