hello web 2.0 bubble. 1 billion dollars?!?! What is twitter doing that is remotely close to them generating any sort of revenue? The site stability is a joke

hello web 2.0 bubble. 1 billion dollars?!?! What is twitter doing that is remotely close to them generating any sort of revenue? The site stability is a joke among the engineers there (a fail whale monitor) , see their presentation at this years velocity, http://velocityconference.blip.tv/ http://velocityconference.blip.tv/ . I understand that twitter is what's hot right now, but if facebook is just reporting cashflow positive and they have an ad model quite some time. How long will it take twitter to get cash flow positive when they seem to not have a game plan yet (atleast a public one)?