AAPL), Google ( GOOG) and, on the retail side, Wal-Mart Stores ( WMT), I think it is prudent for investors to wonder whether Amazon can defy gravity forever. In other words, can it grow into its valuation -- metrics that include expectations imposed by the Street regardless of how outrageous they may be? For example, in its most recent quarter, the company reported 1 cent per share on revenue of $12.83 billion, in line with analysts' expectations. However, while revenue soared by almost 30%, earnings per share fell dramatically by 97% year over year. What's more, over the past five quarters, the company has logged an average of 38.5% revenue growth while net income has dropped by an average of 54% annually during that same span. In spite of this trend, not only has the stock been up as much as 52% this year but, more impressively, it has surged more than 180% over the past three years. Most stocks would have gotten punished for bottom-line trends of this sort. As much as Wall Street seems to love to complain about valuation, in this case Amazon seems to get a free pass. Why? How long will revenue growth be enough absent meaningful EPS results?