"History has shown that whenever companies, no matter how great, get priced above 50 to 60 times earnings, buyer beware. ... But many of today's investors are unfazed by history--and by the failure of any large-cap stock ever to justify, by its subsequent record, a P/E ratio anywhere near 100", Jeremy Siegel, a Wharton professor, in the WSJ, 14 March 2000, about a week after NASDAQ peaked. The article is available at http://www.jeremysiegel.com/.
I have an idea for Bill Gates, the next time Microsoft is considering an acquisition call me. I'm sure I can split my "nominal" fee, of say 10% of the proposed acquisition's price with Professor Siegel and as Nancy Reagan said, "Just say no".