Microsoft says that it is making a big advance toward enabling rival products to work more smoothly on its operating system by disclosing more information about its software.

Today's steps "represent an important step and significant change in how we share information about our products and technologies," said Steve Ballmer, Microsoft's chief executive.

The move follows Microsoft's capitulation to European Union regulators in October after a three-year antitrust battle. At that time, Microsoft agreed to license all its intellectual property except patents for low royalty payments.

Since then, European regulators have begun new investigations into whether Microsoft abused its dominance in software to help its Office and Web-browser products.

The European Commission reacted with skepticism to the latest move, saying that it "would welcome any move toward genuine interoperability."

"Nonetheless, the commission notes that today's announcement follows at least four similar statements by Microsoft in the past on the importance of interoperability," the commission said.

It is unclear whether the steps outlined today by Microsoft are intended to mollify regulators.

Or might it be part of an effort toward an image makeover? An attempt to signal that the software utility is changing its stodgy, corporate ways as it pursues a takeover of Yahoo?

Since 2006, Microsoft has taken baby steps toward open source, with deals with companies like Novell. Other companies—like Google—that have embraced open source have clearly benefited from accessories that were developed to run with their products.

The steps announced today—combined with the battle to win Yahoo—suggest that Microsoft is beginning to realize that it needs to be a more open, more nimble entrepreneurial company focused on the internet if it hopes to mount a serious challenge to Google.

Today, Microsoft said that it would immediately publish more than 30,000 pages of documentation for Windows client and server protocols that were previously available only under a trade-secret license.

It will also show on its website which protocols are covered by Microsoft patents "and will license all of these patents on reasonable and nondiscriminatory terms, at low royalty rates."

And it pledged to not sue open-source developers over products that work with Microsoft software.