Irrational exuberance - the now-famous utterance of Alan Greenspan, referred to the seemingly unending upward spiral of the stock market. Of course, as every investor knows, the stock market plummeted after this comment was made, only to recover and exceed every known record over the next year. Nothing, it appears, could keep this market down: not inflationary pressures, concerns over the Asian economic crisis, lack of earnings in many companies, nor elevated stock prices. Nothing, it seems, could stop investors in their passion for bidding up …