Microsoft's decision to abandon Windows XP with its next browser is a business move meant to push people off the aged operating system, an analyst said today.

It also gives rivals like Mozilla an opportunity to make further inroads into Internet Explorer's market share, said Sheri McLeish of Forrester Research. "XP is in that same world as Office 2003 and IE6," said McLeish. "Microsoft doesn't want to prolong the life of those products."

McLeish was reacting to Microsoft's stated plans not to support its next-generation browser, Internet Explorer 9 (IE9), in Windows XP. Google, which creates Chrome, criticized that decision yesterday during a panel discussion at Web 2.0 on the future of browsers.

"It's not in [Microsoft's] interest to support XP," McLeish added. "They have a vision of moving people ahead on operating systems. That's their business intent."

Microsoft will not craft a version of IE9 for XP because it's adding graphics processor-based acceleration to the browser. That acceleration relies on APIs (applications programming interfaces) that are built into Windows 7 and were added to Vista in October 2009, but that are not available in the older OS.

Noting that Microsoft will meet, and in fact exceed, its usual 10-year support policy for XP -- the operating system is slated for final retirement in April 2014, nearly 13 years after its release -- McLeish said IE9's non-support for the old OS was a business decision by Microsoft. "As time goes on, XP will get less attention paid to it by Microsoft," she said.

She also thought that the noise about XP's inability to run IE9 is a moot point for enterprises. "There are few large customers that don't have an upgrade plan [from XP] in place," she said. "Most firms now running XP are planning to upgrade to Windows 7." IE9 runs on Windows 7.

But a window of opportunity exists for browser rivals, particularly Mozilla, over the next several years as small businesses and consumers continue to run Windows XP. Both Google and Mozilla are working on boosting their Chrome and Firefox browsers' by tapping into hardware acceleration, even on XP.