The exception is the web site for War of the Worlds, the upcoming Steven Spielberg film adaptation of H.G. Wells' tale about a Martian invasion of earth. The performance of waroftheworlds.com was stable Sunday night, but slowed dramatically at the start of the U.S. business day Monday, suggesting a flurry of "morning-after" visits.

The bandwidth-intensive waroftheworlds.com web site uses Flash animation and also downloads a trailer for the Paramount/Dreamworks film, which stars Tom Cruise and premieres June 29. The web sites for other prominent advertisers had few performance problems, including dotcom advertisers Napster, Go Daddy and CareerBuilder, as well as Cadillac, which had performance problems following an ad in last year's Super Bowl.

The Super Bowl is America's highest-rated TV program and the most-watched single-day sporting event. Advertisers spent $2.4 million for a 30-second commercial on the broadcast.