According to , a U.S. Web metrics company, of the browser market in December 2008, down nearly 8 percentage points for the year. However, Microsoft's browser is less popular in Europe, according to French measurement vendor Applied Technologies Internet. In November, the last month that data was available, Applied Technologies' XiTi monitoring site .

Firefox, developed by California-based Mozilla Corp., is the second-most popular browser in both metrics firms' rankings. By Net Applications' numbers, Firefox had a 21.3% market share in December, while XiTi's put Firefox's European share at 28% for the same month. Opera has a very small slice of the overall browser business: 0.7%, according to Net Applications and 3.3% by XiTi's estimate.

The EU's antitrust agency cited the September 2007 ruling by the government's second-highest court as precedent. That decision of the original 2004 verdict, and reaffirmed the illegality of Microsoft's practice of typing Windows Media Player to Windows. That should come as no shock. After the 2007, ruling, that it would embolden the Commission and its chief, Neelie Kroes. "The decision ... is a clear signal to the European Commission that it has the leeway to go ahead," said Herbert Hovenkamp, a professor at the University of Iowa College of Law and a noted antitrust scholar, at the time. "[The commission] now has a license to go ahead, and they have a pretty aggressive posture."

The EU did not specify what it may demand of Microsoft, but left the door open to a solution similar to the 2004 case, when it required the company to offer a version of Windows without the media player. "The Commission may impose a fine on Microsoft, require Microsoft to cease the abuse and impose a remedy that would restore genuine consumer choice and enable competition on its merits," the agency said.

Opera's von Tetzchner had some ideas of his own how the EU could handle IE. "One way would be to include multiple browsers with Windows, and let people choose," he said. "Or Microsoft could provide an icon [on the Windows desktop] for connecting to the Internet, and it would then ask you which browser you want to use."