Microsoft set a record for streaming by broadcasting the Live Earth concerts on MSN on Saturday. The UK concert was the most viewed, followed by Australia, Germany and Japan. MSN had expected that the US show would produce the most traffic, but it came in fourth.

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At the peak, 237,000 people watched simultaneously, Microsoft said.

Microsoft said around 8 million people watched at least parts of the concerts live on MSN. The figure is spread over the 36 hours that the Live Earth shows took place in 10 locations around the world.

Microsoft said the previous most-watched online broadcast was the Live 8 concerts in 2005. AOL streamed live those 10 concerts, and claimed around 5 million people watched live.

Microsoft relied on its existing server farms around the globe to support the stream but beefed up those facilities in preparation, said Lisa Gurry, MSN senior director at Microsoft.

"We used a lot of our existing capacity and purchased additional to ensure we were prepared for the massive amount of traffic we were expecting," Gurry said.

MSN signed the deal with Live Earth to stream the concerts last year and began preparations to support the event in February, she said.

MSN looked back to other popular events it has streamed, such as the NCAA Final Four basketball games, in order to estimate how many people might tune into Live Earth.

MSN expects viewers to continue to visit the site to watch archived video of the concerts on demand. In the week after the Live 8 concerts, AOL surpassed the number of live watchers, recording 8.5 million unique visitors who requested more than 25 million on-demand plays of the concerts.