Response times by top US news sites were slowed as millions of Michael Jackson fans scrambled for confirmation of rumours of his death.
Twitter was the source of many of the initial reports that the king of pop had died, and the microblogging service also struggled under the load.
ABC, AOL, CBS, CNN Money, MSNBC, NBC, SF Chronicle and Yahoo News were all hit by lower response times, according to performance index firm Keynote Systems.
By late yesterday afternoon in the US, the average response time from news sites was almost nine seconds - more than double the normal response time of less the four seconds, Keynote Systems said.
This indicates that consumer demand for news is now online, with people checking social media sites and online news sites before TV, said Keynote Systems
Twitter responded to the overwhelming increase in traffic due to thousands of messages being posted by Jackson fans by disabling some functionality on the network to keep the service working.
"We have had to temporarily disable search results from the logged-in homepage of twitter.com. We are working on the underlying problem and will bring back these features as soon as we can," a Twitter blog posting said.