That's how I understand it. The founders get acquisition money and get to keep the (slightly different) product and users. How often does a deal like that come along?
No, this is a new codebase from scratch. There's zero IP and zero users from Posterous. It's also not a startup -- we are exploring ways to turn it into a non-profit.
Better, turn it into a co-operative? I'm dying to see more co-operatives in the startup space.