Meet the tech world's latest odd couple

Instead of mindlessly mouthing the usual marketing mumbo-jumbo, Microsoft finally decided to publicly embarrass IBM by posting an open letter to the industry that charges Big Blue with limiting consumer choice.

"We just became frustrated," Tom Robertson, co-author of the missive, said in explaining why Microsoft finally decided to let it all hang out.

You normally wouldn't expect something like the mind-numbingly boring world of document formatting to be grounds enough to call out one of your biggest business partners. But IBM also is one of Microsoft's biggest business rivals, and the latest dustup fits with the tempestuous narrative that's defined the companies' interactions over the last quarter century.

This also is a throwback moment. The last time Microsoft and IBM took their love-hate relationship so public dates back to the operating systems war of the early '90s. That's when Big Blue's OS/2 had the briefest of opportunities to challenge Windows as the preferred mainstream desktop operating system.

Any tech reporter covering that era had gads of fun. You'd sit down with midlevel executives from IBM and Microsoft--folks who learned their press skills by mimicking the Stepford Wives--only to get blown away by their uncharacteristic frankness. Real bile would flow.

Of course, billions of dollars in potential sales were riding on the outcome of that contest, so this was much more than simply competitive sport. What's more, there was a personal element at play. IBM was smarting from what it considered to be a mean double cross. Instead of positioning Windows as an operating system for low-end computing, Microsoft Chairman Bill Gates had unleashed his minions to crush OS/2--and ultimately succeeded in doing exactly that.

Call it the invasion of the MBAs, or maybe it's part of the maturing process, but you rarely get straight dope from companies anymore. Everyone's pushing an agenda these days and they're scripted down to the last period of their PowerPoint presentations. Truth be told, there have been meetings where I've been tempted to rip my brains out with a plastic fork.

So it happens that Microsoft must really be fed up. Indeed, Robertson acknowledged that the OK came from the highest levels of the company. Translation: Steve Ballmer is ready to mix it up.

What triggered the latest contretemps? Microsoft accuses IBM of lobbying on behalf of a document format that competes against the default document formats found in Office 2007. For both companies, this is all about looking out for No. 1. After all, if Microsoft were able to standardize its Office document formats, that would chiefly benefit you-know-who. But Microsoft is being careful not to sound shrill. Instead, its representatives say IBM's tactic would only hurt choice and benefit Big Blue's products.

"It's a compete play," Robertson told me.

For that matter, he could have added the following "compete plays":

•  DB/2 versus SQL Server

•  Notes versus Outlook/Exchange

•  Linux versus Windows

That last item particularly gnaws at Microsoft. IBM has done more to promote Linux than any other big technology company. In part, call it payback for the demise of OS/2 and the thorough thumping of the Lotus SmartSuite applications suite. It's also a lot more. IBM has built a lucrative business by embracing open source. And if that winds up giving Microsoft more fits in the process, all the better.

So it is that the biggest technology companies in their respective categories will continue to cooperate in many fields--they have to. They are also destined to increasingly butt heads. When it comes to Microsoft and IBM, it's a case of can't live with 'em, can't live without 'em.