Well, google has jaiku as well as gmail, of course. And there's plurk, and identi.ca, and several others.
identi.ca is promising as it's federated and all that, but when you go there, you see the same thing over and over again: "How do I use this with SMS?" I don't think users understand the enormous cost twitter is just eating for no apparent reason.
And that's the main thing twitter has that is hard to reproduce: SMS in and out at scale. It's not that that's a hard technical problem, it's just incredibly expensive to do that.
identi.ca is promising as it's federated and all that, but when you go there, you see the same thing over and over again: "How do I use this with SMS?" I don't think users understand the enormous cost twitter is just eating for no apparent reason.
And that's the main thing twitter has that is hard to reproduce: SMS in and out at scale. It's not that that's a hard technical problem, it's just incredibly expensive to do that.