It was kind of funny hearing Microsoft CEO Steve Ballmer call Cisco a "good competitor" today at the Mandarin Oriental hotel in New York, where he shared a stage with Cisco CEO John Chambers.

After all, Microsoft itself has been as much as labeled a "bad" competitor by the likes of the U.S. Department of Justice, both the EU and South Korea's respective competition commissions, and countless industry rivals, including Sun, Adobe and others.

When I asked Ballmer whether, in light of all this, he considered Microsoft itself a "good" competitor, he laughed and said he meant that Cisco was a fierce competitor; a company he respects.

I think he was being disingenuous. The real reason for the growing partnership between Microsoft and Cisco is that customers are requiring such erstwhile rivals to create products that truly interoperate, to clarify their product road maps and to allow them to pick solutions from multiple vendors a la carte without paying for or having to resolve conflicts in overlapping technology.

The truth is that Ballmer is not looking to align himself with fierce competitors. He's looking for trustworthy allies--allies that sell proprietary software and solutions; allies not named IBM; allies that play by Microsoft's rules.

For his part, Chambers said he has no illusions about Microsoft, but he believes that Ballmer really shares his vision about the importance of collaboration. "I have a healthy respect for Microsoft," he said with a grin. "But I trust the man."

That's an important distinction.

To its credit, Microsoft could have taken another road entirely by trying to leverage its near-hegemony on the desktop; but that would have once again put it squarely in the cross-hairs of the regulators. Maybe it is learning to play nice with others, if only out of a sense of enlightened self-interest.

Both companies are coming together in the unified collaboration space because of the opportunity it affords to show strong double-digit growth. Chamber said UC is driving Web 2.0 adoption in the enterprise; the market is still highly fragmented, and both companies can approach it better together than separately. "If we're right on this," he said, "we have to work well with Microsoft."

Ballmer noted that percent growth in Vista and Office products "will be significantly less" than growth in Enterprise 2.0-type products. The company's "great relationship with Cisco will accelerate that," he said.

If the engineers at Microsoft and Cisco buy into this shared vision, the ultimate winners will be the customers who adopt this technology first. Companies that buy into UC will find that it changes their culture, and ultimately this is what will make them "good competitors," by giving them a lasting advantage over their competition.