Mr. Phelps in a Visa ad

Over the 'net, US Olympic swimmer Michael Phelps is the most-discussed athlete among fellow Olympians, reports Nielsen Online.

Nielsen Online tracked buzz about Olympic athletes across message boards and blogs posted between August 4 and August 10. Sports included Olympic basketball, gymnastics, beach volleyball and swimming.

Behind Phelps, the second most-mentioned athlete was Chinese basketball player Yao Ming, followed by US basketball players Kobe Bryant and Lebron James:

The web community was especially interested in Phelps' quest to win eight gold medals during the summer games alone, Nielsen said. (The athlete won his tenth total gold medal yesterday.)

Of the four sports covered, swimmers ranked best in terms of volume, comprising 46 percent of total discussion, followed by basketball players (38 percent):

"Swimming is benefitting from a number of interesting stories this year, including Michael Phelps' race for gold, Dara Torres' return to the games and Park Tae-Hwan's win to bring home South Korea's first-ever gold medal in swimming," said Nielsen Online's VP of media analytics, Jon Gibs.

"As other events build momentum and the track and field competition begins, it will be interesting to follow the fan favorites online."

Phelps, whose merits some believe could make him a brand name like Michael Jordan or Tiger Woods, was critiqued last month for donning a Visa swim cap during the US Olympic trials in Omaha. The credit card brand has been actively sponsoring Phelps, featuring him in TV and mobile spots, since early this year.

One Visa ad, which will run throughout the summer Olympics, jokingly suggests Phelps possesses the assets of a fish or dolphin:

The company — which has sponsored Phelps since 2002 — released a special-edition Phelps ad yesterday, shortly after the swimmer won his tenth gold medal, setting a record for the most career Olympic golds. Given Phelps' rising star, Visa will likely leverage its affiliation through the year.