Thomas Vinje, the lawyer representing companies including IBM, Oracle and Red Hat, as well as Opera, the browser manufacturer that sparked the current antitrust investigation against Microsoft, described the software giant's moves as welcome.

Microsoft has offered to carry a browser "ballot," making it easier for even novice users to choose another browser besides IE for their default link to the Internet. It also has offered to promote interoperability between third-party products and a number of crucial Microsoft products, including Windows, Windows Server, Office, Exchange and SharePoint.

"The devil will be in the details, but in principle Microsoft's acceptance of a consumer browser ballot is a very welcome development," Vinje said, adding similar remarks concerning the interoperability offer.

The European Commission also welcomed the move, saying it would now investigate the effectiveness of the offers, focusing initially on the proposal to restore competition in the browser market.

The Commission charged Microsoft in January with distorting competition by bundling its Internet Explorer browser together with its omnipresent Windows operating system. The regulator said this puts rival browsers at a disadvantage and proposed a ballot screen listing browsers that users could then choose from.