11.   By talking about higher interest rates and irrational exuberance, Greenspan sent bond prices lower and interest rates higher on Wednesday.

12.   Future profit growth, then, is the key criterion, in the Greenspan view, for stepping over the line into irrational exuberance.

13.   Greenspan caused Wall Street prices to tumble earlier this year when he warned that soaring share prices reflected irrational exuberance.

14.   He also explains what managers of the next wave of Internet companies must do to avoid the irrational exuberance of the dot-com bubble.

15.   He did not claim that irrational exuberance had actually infected stock trading, driving up prices in pure speculation beyond their true value.

16.   However, experts cautioned investors against irrational exuberance.

17.   History offers more than a few examples of irrational exuberance followed by irrational pessimism.

18.   In comments before the Senate Budget Committee, Greenspan did not repeat warnings about irrational exuberance but did compare investing in Internet stocks to playing the lottery.

19.   Irrational exuberance is what brings most Boston contenders to their knees by the time they get to the Haunted Mile.

20.   It represents genuine progress, driven by competitive pressure and innovative response, not transient policy or irrational exuberance.