A lesson learned from app.net is that when all conversations on a social network are meta-conversations *about that social network* you get an incredibly boring, self-centered echo chamber that's very unappealing to most audiences (which, in turn, makes it more boring and self-centered).
Disclaimer: not *all* conversations on app.net were about app.net. Far from it, actually. Still, it was such a prevalent topic that it might as well have been the only one. I'm convinced this is what killed it.
@owlasylum it is, and to some degree this is probably needed. It was a year down the line when app.net started feeling like a self-centered monoculture because it couldn't stop talking about app.net…