http://www.valuewalk.com/2012/07/facebook-inc-fb-zynga-inc-znga-and-groupon-inc-grpn-ipos-meet-their-comeuppance/
"Facebook, we warned our readers about numerous times, including a piece on May 7th, 10 days before the IPO. We noted the absurd valuation, and models which gave the stock a buy based on 22x 2015 estimated earnings. The model assumed that 43% of the world would be using Facebook."
