Microsoft Sets PST Free -- And Everybody WinsMicrosoft Sets PST Free -- And Everybody Wins

By opening its Outlook data format, Microsoft might lose a few customers. But it will also give many others a good reason to stick around.Yesterday, Microsoft announced that it would release the documentation for its PST file format. This format is to Microsoft Outlook what the DOC and XLS formats once were to Microsoft Office: A proprietary black box that third-party developers attempted to reverse-engineer at their own risk.

The company will release the PST documentation under its Open Specification Promise, which basically assures outside developers that they won't get sued, even if they use the documentation to build a competing application.

The announcement won't have a major short-term impact. Microsoft is being cagey about committing to an actual release date, most likely because it will take a while for the company's own engineers to create usable documentation. PST is a notoriously complex and difficult format, and even different versions of Outlook tend to have serious compatibility problems.

In the long run, however, releasing the PST documentation will allow developers to do all kinds of interesting things: Developers will thus be able to read, create, and interoperate with the data in .PST files in server and client scenarios without concerns about patents, and without the need to contact Microsoft. Anyone will be able to implement the .PST file format on any platform and in any tool, using the programming language and platform of their choice. The company says that providing access to the documentation will facilitate interoperability by enabling customers and vendors to access their data in .PST files across a variety of platforms. Organizations that need to exchange key corporate data in and out of Outlook, upload to the cloud, or comply with corporate governance policies, will find this particularly useful. All of this might sound like a problem for Microsoft. Certainly, the company won't be able to lock customers to Exchange and Outlook the way it could in the past.

Then again, many Exchange users were already dealing with a tough question: How long do you keep such important business data tied to a proprietary format before the interoperability issues simply become too much to bear?

Microsoft just answered that question for them, turning PST from a black box into a de facto industry standard. Companies that currently use Outlook and Exchange can continue to do so, even as they adopt other, complimentary technologies.

Some firms will take this route because they consider Microsoft Outlook a valuable part of their IT infrastructure. Others will take it because it offers the path of least resistance.

Either way, both Microsoft and its customers win in the long run. There's nothing terribly altruistic about the company's decision; it simply makes good business sense in an era when proprietary data structures -- no matter how deeply entrenched they happen to be -- cause far more trouble than they are worth.