Bebo claims 12.9% marketshare.

MySpace may be the king of social networking sites in the U.S., but a new report from web research firm Hitwise says that it is playing second fiddle to rival Bebo in the U.K.

And while MySpace has its eye on world dominance, it remains in stiff competition with other social networking destinations elsewhere around the world, Hitwise data suggests.

Bebo for the first time edged past MySpace in weekly market share of UK Internet visits to become the most visited social networking site in the region for the week ending August 5, according to Hitwise.

The site claims 12.9% marketshare in the U.K. vs. 12.49% for MySpace. The research firm attributed the most recent surge in visits to Bebo the launch of a new music service two weeks ago called "Bebo Bands".

Bebo's market share is up 17% during that time while MySpace has seen its market share decline slightly. The site now ranks as the No. 11 most visited site on the internet in the UK, up from 17 two weeks ago.

Hitwise notes that signs of a shift first emerged in May when Bebo had surpassed MySpace in daily visits on two individual days in May.

“In May, we predicted that Bebo would overtake MySpace in share of UK visits at the start of the new school term, as the summer is typically a slow time for the site. The launch of Bebo Bands brought members back to the site and it shot ahead of MySpace ahead of our projection,” Hitwise analyst Heather Hopkins said in an Aug. 9 blog post.

The jump in traffic for Bebo comes as press speculation is mounting that Bebo may be primed for a takeover by a larger media company, possibly MTV parent company Viacom.

MySpace remains dominant in the US with 50.18% marketshare, Hitwise says. However MySpace’s foothold in other markets around the world appears less secure. MySpace is tops in Australia with 16.68% marketshare. But Hitwise reports Bebo leads in New Zealand, while Xanga is the front-runner in Hong Kong and Friendster leads in Singapore.