people keep beating up on this too much
markets are supposed to be efficient...you cannot fake the market upwards for a long time if it "wants" to go down or will have to spend a lot of money trying.
Was there a bubble in AMZN in 2000? 2001-2002 said that it was, and Henry Blodget with his $400 (now $100) target was driven out of Morgan Stanley as a result, but 2015 clearly says that it WASN'T a bubble afterall. Time has a habit of fixing old misconceptions.
Check out this AMZN chart on max range:bubble-crash-steady rise.
http://finance.yahoo.com/echarts?s=AMZN+Interactive#symbol=AMZN;range=my