The software giant, which agreed earlier Thursday to distribute movies and TV shows for big media companies, has seen Soapbox fill up with unauthorized clips since a test version of the site launched last month.
No new subscribers will be accepted, but anyone who has already signed up for the site, said Adam Sohn, a director in Microsoft's online-services group.
Microsoft stood to be embarrassed by theon Soapbox. There was a real possibility that the company could have found itself distributing video from News Corp. and NBC Universal, at the same time another one of its units was hosting material stolen from those same companies.
Microsoft, AOL and Yahoo have agreed to be part of athat also includes NBC Universal and News Corp. The new video network, scheduled to debut this summer, will feature full-length programming, movies and clips from at least a dozen television networks and two major film studios.
Copyright issues have become a central issue to the nascent online video market. On YouTube, the largest video-sharing site, there are thousands of clips posted to the site without the copyright holder's consent.
To help create a filtering system that would prevent the uploading of copyrighted video clips, Microsoft licensed digital-fingerprinting technology from Audible Magic.
Sohn said the changes were not forced on Microsoft by its new partners, although he acknowledged that some of the content providers were very interested in how his company planned to clean up Soapbox.
"This software company is aligned very closely with the notion of intellectual-property rights," Sohn said. "We feel this is the right time to make these changes and stand up to do the right thing."