Others in the open source community weren't as skeptical of Microsoft's motivations.

Jim Zemlin, executive director of The Linux Foundation in Beaverton, Ore., said the latest effort is "very similar to language that they've expressed in the past," with a few unique differences. "They specifically announced that open source is something they want to work with and interoperate with, [while] not describing Linux and open source as a 'cancer' as it once did.

"That's good stuff, that's new, that's meaningful," Zemlin said. "They see that the world and their customers and regulators and governments around the world are demanding openness and they really mean it this time. Microsoft has to see this new requirement where openness is a new defining technology, not a closed, single monopoly. It's a clear acknowledgment that that's where the world is moving. At the same time, they've said this before, so it will take time to see if Microsoft is going to walk their talk.

"Take OOXML, their alternative document standard, off the table and support the existing standard, ODF; I think that would show people that they're willing to walk their talk."

Juergen Geck, CTO of Open-Xchange and former CTO of SUSE Linux, said the new Microsoft initiative is "good news for us and the market at large."

Geck said the principles don't necessarily mean that licensing fees would have to be paid to Microsoft in every case, even if interoperability is improved. "It's going to be much more complicated than dealing with an [entirely] open environment, but we're dealing with Microsoft. It's a good step in the right direction. They could do more, but it doesn't put us in a position of complaining about them in general. Ninety-five percent of the market wants to run Windows. It's not fair to blame Microsoft for that."

Meanwhile, Bill Hilf, Microsoft's platform technology strategy general manager, said the effort could show the company in a better light in the open source and free software communities.

"This makes us more difficult to be the enemy, because we're providing what they asked for," Hilf said. "The real issue for open source developers related to Microsoft, in the broad sense, has not been about access to Microsoft source code -- although that's the issue for what I'd call open-source theologians -- but instead about access to Microsoft protocols and APIs. This is giving them that. They can now write products with the same protocols and APIs that we use to build our products."

So far, "the reaction has been very, very positive," Hilf said. "I've gotten lots of e-mails from open-source developers, who said, 'This is what we've been asking for.'"

Hilf, who went to Microsoft four years ago from IBM, where he led that company's Linux and open source software technical strategy, said "we're always looking at ways we can do better with our own software."

Computerworld's Gregg Keizer contributed to this story.