Two of IT's archest rivals -- Google and Microsoft -- are meeting in the cloud, whether they like it or not, and they are likely to be joined by IBM, which is already residing there. That is one interpretation that can be drawn from Monday's "Evening in the Cloud" session at Enterprise 2.0.

In his "State of the Productivity Union" address David Berlind, TechWeb.com chief content officer, noted that just one year ago at least year's Enterprise 2.0 event, Google and Microsoft were at two far ends of the cloud computing spectrum.

"Both were far apart," said Berlind. "Microsoft had the most widely shared formats," while Google created its documents "in the Web." Now they are moving closer to the middle as Microsoft introduces Web-accessible free-of-charge apps including Word and PowerPoint, while Google beefs up its offline Gears applications.

Berlind noted that Microsoft began "feeling the heat from Google" so they became negotiable, and then Google, too, became negotiable on its $50 per user price.

Another speaker, IBM's Sean Poulley, indicated he favored a wide-open approach to cloud computing for enterprises and he said an open cloud computing environment will be most beneficial to enterprise CIO managers.

"We've embraced openness," said Poulley. "The key is not to lock-in. We've been very focused on openness for 10 or 15 years." Poulley said openness tends to protect the investments of IT enterprises and eschews "migration for the sake of migration."

Poulley, who is VP of online collaboration services, Lotus software, IBM software group, said IBM's openness drive for the cloud didn't come from IBM itself, but rather from its users. Noting that IBM was in the vanguard for protecting open document formats, Poulley said users who were concerned about protecting their documents asked IBM to champion their cause to ensure that document formats be kept open. "This happened not because we thought of it," he said, "but because our customers came to us."

Like other speakers at Enterprise 2.0, Poulley said cloud computing is evolving rapidly. To keep up, he observed that Lotus is growing its Notes technology to be additionally compatible with cloud computing.

An example of IBM's commitment to improving cloud computing solutions is its acquisition weeks ago of Cast Iron Systems, whose OmniConnect cloud integration platform integrates public and private cloud services with on-premises applications. The Cast Iron platform supports many enterprise applications ranging from SAP, Oracle, and Microsoft to Lawson and Amazon EC2.

What does IBM have in store for the cloud?

Poulley said there will likely be future cloud announcements for mid-range enterprises in the coming months. He added that additional open interfaces are not only making cloud computing easier for users, but IBM business partners are lining up to participate in the growth of cloud computing as the openness wave continues to catch on.

Other participants in the session included Yuvinder Kochar, VP of technology and CTO of The Washington Post; and William S. McNee, founder and CEO of Saugatuck Technology.

Attend an InformationWeek virtual event on creating and leveraging the private cloud and how that could affect your business' most critical systems and information. It happens June 23. Click here to find out more and register.