Lots of interesting points made here. If I could add only a few data points, I would say the following. I have taught a very successful class on Investor pitch

Lots of interesting points made here. If I could add only a few data points, I would say the following. I have taught a very successful class on Investor pitching in SF for 6 months. I have had between 10 and 50 students per class, always sold out, even when I raised prices... (http://fundraisingviparisoma.eventbrite.com/)until http://fundraisingviparisoma.eventbrite.com/)until end of March. Then, in April, I had to cancel two classes because I had too few students, and I only have 10 next week in a venue when I never had less than 20. It just tells me that we are at the end of a cycle, when everybody who drunk the "Social Network Movie kool aid" thought they could create a Groupon for India, a language learning start up or an Opentable for Hair Salons. It's a good thing for everybody actually. Now as for Facebook's valuations, the question is - will Facebook bring as much traffic to applications in the future than Google did to commerce websites. My belief is yes (look at Viddy, SocialCam, Zynga, Pinterest, Draw Something if you need examples). In that case, Facebook, like Google in 2004-2008, will grow into a 100B-$200 valuation (which does not mean that I think it is the best stock purchase to do, the big money on Facebook has been made already by earlier investors). Same for Pinterest. If Pinterest users convert like crazy, then they will be able to demand emerchants to "pay to play" and... they will.