Pump.io is a really great network if you give it a chance and invest some time and effort on it. Sadly many people doesn't do that.

Also sadly, many identi.ca users didn't give it a chance when identi.ca became part of this network.

As for the several incompatible "free networks".. that's what the W3C Social WG is trying to solve. But these things take a lot of time, a lot of work, and people willing to agree on things.