From what I read, they aren't aiming for an IPO, so they are definitely here to stay - or at least they think so. Costolo's Charlie Rose interview made it soun

From what I read, they aren't aiming for an IPO, so they are definitely here to stay - or at least they think so. Costolo's Charlie Rose interview made it sound like Twitter and its success happened completely by accident, and the company will now try to capitalize on it instead of trying to understand what made Twitter successful and grow that aspect of it. It's only going to get worse from here.