One of the constant issues faced by any social tooling, and I don’t want to say “network” as that’s not really a good choice of words in my opinion, is a “network affect”.

The idea of your friends’ friends’ get dragged along to use the platform. So far, every federated social solution has had the issue of network affect being near zilch with regular people. Meaning it spreads best through highly interlinked groups, such as the so called tech-o-sphere and the extremist political movements.