The market is starting to demand that companies that have huge multiples start to earn their multiples.
FB, GOOG, MSFT, APPL and CSCO are proabably all ok as they can hit their targets with relative ease and don't carry a burdensome multipel, but hype based companies like TWTR, LNKD and others are about to be in a world of hurt, I wouldn't want to be a shareholder in any of those companies:(
This is probably going to be especially painful for the SAAS companies that just IPO'd, I don't think they'll get much time to prove they are worth their multiples and they have the double whammy of coming out of employee lock up periods pretty soon.
AMZN is the one wild card, I would have thought their free pass expired long ago but they are the sole exception that I can think of.
EDIT to respond to the question about FB's multiple, Most people still believe that FB has the ability to turn on a switch and make more money, ie they are artificially making less than they could fro the sake of growth, just like AMZN.