CAN the leopard shed his spots? This month, Microsoft is offering Web surfers in the United States a seductive viewing treat. In conjunction with NBC, the software publisher is offering thousands of hours of free video direct from the Olympics in Beijing.

The service is being hailed as a bold experiment in delivering on the original promise of the World Wide Web. For the first time, it will be possible to watch specific events on demand as well as to watch many of the less popular sporting events like cycling and race walking, which in the past have received scant attention in mainstream television coverage of the games.

But there’s a catch.

To view the video, it will be necessary to download a Microsoft Web browser software component based on a new proprietary technology, Silverlight, that is intended to make it possible to display interactive animations, graphics, audio and video, all within a fixed window inside a Web browser display.

Microsoft executives say Silverlight will “light up the Web” with multimedia content.

But for many industry executives who compete with Microsoft, the world’s largest software company, the Silverlight strategy recalls a federal antitrust case in which Microsoft was found guilty of using its market muscle to stifle competition from the Web.

Which is tougher? The competition at the Olympics or competing with the dollars and control of Microsoft and NBC?