"This is a temporal problem," said Gavin, referring to the time it will take XP to disappear. "Either we build a better experience or we don't. Pushing the Web forward, that's the best way to keep users."

Hilwa said that Microsoft made a tough decision to leave Windows XP behind, and that it will take time before anyone, including Microsoft, knows whether that bet paid off.

"I understand the agony on this," said Hilwa. "Microsoft made a complex cost-benefit analysis for supporting XP, and placed their bet. We will have to see how it plays out."

Net Applications calculates browser usage share with data obtained from the 160 million unique visitors who browse the 40,000 Web sites the company monitors for its clients. Its can be found on the Net Applications site.

Gregg Keizer covers Microsoft, security issues, Apple, Web browsers and general technology breaking news for Computerworld. Follow Gregg on Twitter at or subscribe to . His e-mail address is .