NEW YORK—High-tech publisher Tim O'Reilly has predicted that Microsoft will emerge as a leading proponent of the open Web, a statement that must seem highly unlikely to a computing world accustomed to Microsoft's love of fostering its own proprietary operating systems and development languages.

"Microsoft is going to be one of the great allies of open standards," O'Reilly told thousands of people at the Web 2.0 Expo Nov. 17. That statement picked up where O'Reilly left off in "The War for the Web," a cautionary blog post published Nov. 16. He wrote:

"Microsoft will emerge as a champion of the open Web platform, supporting interoperable web services from many independent players, much as IBM emerged as the leading enterprise backer of Linux."

But he didn't qualify that statement or explain how Microsoft would do this. O'Reilly used the blog post as a lead-up to his Tuesday keynote at the Web 2.0 Expo he helped foster years ago.

Toward the end of his keynote, which discussed how cold wars between companies are paving the way for mutually assured destruction, O'Reilly said Microsoft's recent deals to index Twitter tweets and draw on Wolfram Alpha's APIs for computational data show a shift in its willingness to work with other Web companies.

While O'Reilly was making his case about the various factions fighting it out for our interest (and dollars) online, more evidence of this openness emerged at Microsoft's Professional Developers Conference.

Microsoft Chief Software Architect Ray Ozzie said Microsoft would release its Windows Azure cloud services operating system in 2010. But the big news was that instead of just supporting the company's .NET programming language, it will support PHP, MySQL and other open-source tools.

For example, Automattic founder Matt Mullenweg said his company is launching a site called OddlySpecific.com that runs on SQL Azure. That Microsoft would trumpet the existence of a customer so early on in Azure's young career is not big news, but Automattic makes WordPress, a blogging platform based on open-source tools.

Betanews' Joe Wilcox, who has covered Microsoft extensively for the last 15 years, noted:

"From a marketing perspective, it was a stunning announcement, since Automattic uses open-source tools like Apache and MySQL. The message: Azure isn't just about Microsoft products or development tools. I must say it was simply shocking to see WordPress creator Matt Mullenweg on the PDC stage."

So there is something to O'Reilly's position that Microsoft is opening up. However, O'Reilly said companies such as Microsoft shouldn't open up only because they are trying to catch up to Google in the field of cloud-based computing.

"Don't do it just because you're the underdog," O'Reilly said, pointing to IBM's embrace of Linux to battle Microsoft and Google's launch of OpenSocial to contest Facebook as other examples of such defensive jabs. Do it, he said, because it's the right way to do business in the Web economy.

His parting comment for the audience: "As you build services, do what you do best, link to the rest."  

eWEEK will have more this week on O'Reilly's cautionary tales about computing cold wars between Google and Apple and Facebook and Twitter.