Tonight's Sounders game is an especially big opener for Major League Soccer, which is using the Seattle game to debut new online services for fans, including a high-def streaming video service.

Not coincidentally, a lot of the services are based on technology from Microsoft, which is a major sponsor of the league and the Sounders.

U.S. soccer fans on average are more technologically inclined than the general public, and the league is counting on new digital services to keep growing its popularity, said Chris Schlosser, MLS director of digital strategy.

Schlosser, a former product planner in Microsoft's MSN group, led the development of entirely new Web sites for the league and individual teams that are also debuting at today's game.

"It's one of the most significant investments our [league] ownership group has ever made,'' he said. "They clearly see our fan base is digital and the future growth of our league is driven by continued growth in the digital space."

The new online video service, called MatchDay Live, will stream up to three games at once and provide digital video recorder-like features, including pause, rewind and "instant replay."

The player has a banner listing games across the league, which can be clicked to display "picture in picture" thumbnails while a game plays in the main screen.

Other features include live chat for sending instant messages to other fans and a "Field Tracker" with an aerial display showing highlights during a game.

"This really changes the experience for the MLS,'' said Chris Wagner, executive vice president of NeuLion, a New York-based company that built the player for MLS.

NeuLion provides similar services for the national hockey and football leagues and schools such as the University of Oregon, running their Web sites and online video subscription services.

For $39.95, MatchDay Live subscribers will get access to up to 160 live games, plus on-demand replays, during the 2010 season. There are about 225 games during the season; subscribers won't be able to stream them all because of restrictions on streaming local games live and on games that are being broadcast nationally on TV.

Playoff games will cost extra. Prices haven't been set, but Wagner said a playoff package will probably cost $10 to $15.

MatchDay Live is built on Microsoft's Silverlight platform, the same system used to stream the Olympics and by Netflix to build its online video service.

Microsoft and the MLS also worked together on a mobile app that will be highlighted in a new mobile application store coming later this year.

But the new Web sites are based on open-source software. MLS built and runs them itself, after previously outsourcing its sites to Major League Baseball.

The MLS sites were "built for the social Web" with Twitter and Facebook integration and content provided by a staff of veteran soccer journalists now working for the league, Schlosser said.