At Yahoo, the article headlined "Michael Jackson rushed to hospital" got the most hits of any other story ever posted on the company's home page with 800,000 clicks within 10 minutes. "Also, the news area on our front page experienced five times the amount of traffic it normally receives," Yahoo said in an official .

Yahoo News broke its record of unique visitors with 16.4 million; the previous record was 15.1 million visitors U.S. election day last year. In Yahoo Music, 21,000 people left comments on a blog post about Jackson, while more than 4,000 images related to the music star have been posted on Flickr in the past day, the company said

Facebook, the world's most popular social-networking site, experienced an increase across its core actions, like the posting of messages, notes and links on member profiles, a spokeswoman said via e-mail.

"Status updates in particular saw an increase of more than 3x the amount than usual within an hour of the MJ news breaking and remained well above our usual numbers for several hours," the spokeswoman said.

Jackson died unexpectedly at age 50 from a heart attack in Los Angeles as he was reportedly getting ready to launch a comeback. One of the biggest stars in pop music history, on par with icons like Elvis Presley and the Beatles, Jackson saw his star fade in the 1990s. One of the most successful recording artists of the 1970s and 1980s, Jackson later became more well known for scandals including accusations of child molestation and controversies over his multiple facial plastic surgeries.