Michael Jackson's sudden death Thursday rocked Twitter and news Web sites as people swarmed the Internet looking for the latest developments and analysis surrounding the death of the pop-music icon.

Twitter, the popular microblogging service that's experienced exponential growth in the last year, was flooded with thousands of Jackson-related messages immediately after reports of his death circulated. Demand was so overwhelming that performance slowed considerably, and Twitter said it had to disable temporarily the search field on its users' home pages.

"We saw an instant doubling of tweets per second the moment the story broke," Twitter co-founder Biz Stone told the New York Times. He added that the volume of Jackson-related messages hit 5,000 per minute at its peak.

"This particular news about the passing of such a global icon is the biggest jump in tweets per second since the U.S. presidential election," Stone told the paper.

Stone wasn't immediately available for further comment.

To be sure, Twitter wasn't the only site that was on overload Thursday as Web sites for Time Warner Inc.'s (TWX) AOL, Walt Disney Co.'s (DIS) ABC, CBS Corp. (CBS) and the Los Angeles Times all experienced "marked slowdowns in performance," according to research from Keynote Systems Inc. (KEYN), which measures Internet performance.

Beginning at 5:30 p.m. EDT, "the average speed for downloading news sites doubled from less than four seconds to almost nine seconds," said Shawn White, Keynote's director of external operations. The average availability of sites dropped from almost 100% to 86% before returning to normal by 9:15 p.m.

Google Inc. (GOOG) also experienced difficulties as searches for Michael Jackson immediately after the news broke resulted in error messages rather than a list of results.

But delayed results and overloaded servers represent special cause for concern for Twitter as developing search is seen as a way to generate revenue.

Twitter's been praised for its rising popularity but also criticized for its inability to develop a business model. Google and Microsoft (MSFT) have been rumored to be interested in striking partnerships with Twitter as its real-time search capabilities could help advertisers better target consumers.

But current troubles "don't bode well for Twitter's prospects as a real-time search engine, which many believe is likely the service's most valuable feature," Joseph Tartakoff wrote in a post on the technology blog paidContent.

-By Steven Russolillo, Dow Jones Newswires; 212-416-2180; steven.russolillo@dowjones.com