Microsoft's error could have cost its competitors new customers, according to Anderson. "After accounting for the aggregate impact on all the browser vendors, it seems like this technical glitch decreased downloads and diminished the effectiveness of the remedy ordered in the 2009 Commitments."
The cost to Microsoft could be a fine of up to 10 percent of its worldwide turnover -- although that figure is the legal maximum, not an indication of what a possible fine would be, according to the Commission.
Loek is Amsterdam Correspondent and covers online privacy, intellectual property, open-source and online payment issues for the IDG News Service. Follow him on Twitter at @loekessers or email tips and comments to email@example.com