The VC answer is good, but I think growth is necessary to sustain the social part of a social network as well. I joined Twitter very late, to get news when the

The VC answer is good, but I think growth is necessary to sustain the social part of a social network as well. I joined Twitter very late, to get news when the Boston marathon bombing was happening, and while the feeling that twitter is a forum that covers the whole internet is still there, it's at late stages. Most people are well and truly over the idea that twitter is worthwhile in and of itself, and most people are pretty much following as many people as they want to be. It's much more likely that long time users are cutting down on follows than adding new ones. It still has a culture where you can talk to strangers on the internet, but a pretty big etiquette has grown up around that, and that can also be intimidating coming in late.