Mixi, Japan's biggest social network service, has launched a video file-sharing operation that it says will "revitalize" communication between the company's eight million users.

Videos shared through the service cannot be longer than five minutes, and Mixi president Kenji Kasahara says Mixi will be on the lookout for material that infringes copyright.

"We can't check all the content that's uploaded, but we do have 'patrols'," Kasahara said at a press conference Feb. 7. He added that he hopes that a way will be found to upload and share copyrighted content legally so that content owners, Mixi and Mixi users will all benefit.

Kasahara said that Mixi has an 87% share of the Japanese SNS market and is the third-most visited Web site in Japan, after the local versions of Yahoo and Google. He added that one-third of Japanese between the ages of 20 and 24 are Mixi users. Mixi claims to be approaching 10 billion page views per month.