Critical mass is just one of those things that will be a flaw until it isn't. Facebook has this "decisive competitive edge" in that the fact that it is seen as

Critical mass is just one of those things that will be a flaw until it isn't. Facebook has this "decisive competitive edge" in that the fact that it is seen as the only alternative is what reinforces it being the only alternative. It's good that these other solutions are free and open source because most commercial competition would dry up and fail. But for these things that bump along and grow slowly in a sustainable way, they might actually approach an inflection point where things will snowball. At least I hope so!