TMZ, the carnivorous celebrity news Web site, is accustomed to beating other media outlets on the stories that shape the entertainment world. On Thursday, it not only scooped every other outlet by announcing Michael Jackson’s death, it apparently beat the coroner’s office, too  by six minutes.

The blog  owned by the media conglomerate, Time Warner, but operated as a Web-traffic-fueled fief in Hollywood  seemed to have sources everywhere: at Mr. Jackson’s mansion; in the ambulance; and in the corridors of the U.C.L.A. Medical Center. TMZ’s short post about the death was published at 5:20 p.m. Eastern time.

For more than an hour, TMZ was essentially the only outlet claiming that Mr. Jackson was dead. Television and newspaper journalists read the TMZ report but largely held off on repeating it, for fear of making a mistake. Still, the bulletin traversed the Web with remarkable speed, creating a stark divide: on the Internet Mr. Jackson was dead, and on TV he was still alive.

By the early evening Mr. Jackson’s death had become the No. 1 story on newscasts worldwide. The intense, almost voyeuristic interest strained many Web servers, crashing AOL’s instant messaging service and even tripping up Google News for about half an hour. Tens of millions of viewers watched hastily arranged tributes to Mr. Jackson on nearly a dozen channels.