Reversing an earlier decision that would have made its next Web browser less compatible with existing Web standards, Microsoft yesterday announced that Internet Explorer (IE) 8 will use standards-based rendering by default. The announcement comes on the eve of MIX'08, Microsoft's Web development conference, held this week in Las Vegas.

"IE 8 has been significantly enhanced, and was designed with great support for current Internet standards," says Microsoft Chief Software Architect Ray Ozzie. "Our initial plan had been to use IE 7-compatible behavior as the default setting for IE 8, to minimize potential impact on the world's existing Web sites. We have now decided to make our most current standards-based mode the default in IE 8."

The move should cheer proponents of Web standards who had complained about Microsoft's original plan for IE 8, which will support three Web page rendering modes. The first, called Quirks mode, is designed for compatibility with older Web sites that were made with IE 6 or older IE versions in mind. The second, IE 7 mode, will render Web pages identically to IE 7, the current version of the browser. The third mode, now the default, will more closely adhere to existing Web standards, as do competing browsers like Mozilla Firefox and Apple Safari.

This is no small change for Microsoft, which has always valued backwards compatibility over forward-leaning technologies. On the other hand, this decision may also remove some legal questions hanging over the company, including an EU antitrust investigation into Microsoft's decision to bundle IE with its dominant Windows products. If IE 8 renders Web sites according to Web standards by default, the company's competitors can't complain that the browser was designed to lock-in customers.