And so it was in July 1998 with the promise Internet profits, when the stock value of the online bookstore Amazon.com continued multiplying past the combined value of its much larger offline competitors despite growing losses. Rocketing prices of Net stocks arched earthward in the fall, but the bout of gravity soon passed. By early December America Online, Yahoo and Amazon were colossi of the stock market, with "market caps" ($44 billion, $21 billion, $12 billion, respectively) that dwarfed name-brand airlines and investment banks. Feeding the frenzy, lesser companies with little but .com in their names staged fantastically profitable public offerings that valued money-losing million-dollar revenues at billion-dollar prices.

How to explain the mania? Obvious excitement over the Internet's promise -- no duh! -- plus a new breed of online investors placing bets through low-commission web brokerages. There won't be enough seats for everyone when the music stops, but knowing that doesn't make it any easier to leave the party early.