Is Amazon.com's stock price getting too expensive? That's what GigaOM is wondering.

Amazon has been trading at 55.7 times its forward earnings, according to GigaOM. Look what happened the last time it got this high. In October 2003, when the company's P/E ratio was at 58.9, the stock began a slide from $60 to $25.

Amazon's stock price is just above the $69 mark, at last check. A year ago it was at $35.