Gates: open source lacks interoperability

"Open source is a methodology for licensing and developing software that may or may not be interoperable," Gates said. "Additionally, the open source development approach encourages the creation of many permutations of the same type of software application, which could add implementation and testing overhead to interoperability efforts."

Industry watchers observed that Microsoft has made advances in encouraging interoperability both through the design of its products and its partnering relationships but that the company can do much more to help ease IT systems management for its customers.

David Smith, an analyst with market research company Gartner, said Microsoft has done more than just talk about interoperability. He predicted the company will rely heavily on Web services as a vehicle for easing future software integration headaches.

"I would say that they've done more than just give lip service to the idea of interoperability," Smith said. "They'll continue to work on it where it doesn't threaten product revenues, but there has been some improvement over the years."

Al Gillen, an analyst with IDC, said Microsoft will need to continue to work more closely with its largest partners in order to exhibit true progress with interoperability. He said the company's vision will likely establish interoperability standards and push other vendors to follow suit.

"I'm still waiting to see more progress result from Microsoft's partnership with Sun," Gillen said. "There's been a lot of talk, but few product specification announcements. Getting Windows to work better with Unix technologies is one area where you could imagine some real improvement."

Gates frequently uses his "executive emails" to help steer Microsoft's strategy in public. Most recently, he used the medium to detail the company's progress with improving security issues in its products.