Silicon Valley's math is getting fuzzy again.
Internet companies with funny names, little revenue and few customers are commanding high prices. And investors, having seemingly forgotten the pain of the first dot-com bust, are displaying symptoms of the disorder known as irrational exuberance.
Consider Facebook, the popular but financially unproven social network, which is reportedly being valued by investors at up to $15 billion. That is nearly half the value of Yahoo, a company with 38 times the number of employees and, based on estimates of Facebook's income, 32 times the revenue.