we look more closely at all this with jessi hempel who follows the tech world for "fortune" magazine. and josh bernoff, a senior vice president at forrester research and the author of two books on social media. josh bernoff, let's start with you. are we watching the inflation of tech bubble 2? >> i certainly think there's no rational way to understand these valuations. i want to be clear here-- social is extremely exciting. there's a lot of business perspective, a lot of optimism that goes along with it, but i think these valuations are based on where people think the next buyer will come from, and not on where the actual revenues of these companies are going. >> jessi hempel is it a little different this time in that some of the companies we are talking about actually do have revenue streams and do make money? >> that's exactly right. i agree with josh. i think that it's impossible to explain exactly what's going on here with the exuberance, but this is not the first bubble. and i think when you say "bubble" people immediately think win 1.0, they think pets.com. this is not that. the