how much money do you think they can make with that?
I don't really want to offer my random guess against your random guess of "not much money". Why not wait and see? What vested interest do you have in seeing Twitter fail?
I hope Twitter makes a lot of money and lasts for a long long time. It will be good for the world.
I have no vetted interest in seeing Twitter fail, nor do I think it will. I think Google and Bing will keep it afloat for a long time until they figure out how - or if - they are really interested in the so-called "real-time web".