Microsoft has released the Microsoft Office binary file formats (doc, xls, ppt) under Microsoft Open Specification Promise, which effectively says: “We will never assert our patent claims against you for making, using, selling, offering for sale, importing or distributing implementations of the covered specifications.”

Indeed, these file formats are pretty complicated (it takes more than 200 pages to spec the Word .doc file format; Joel Spolsky explains why). But releasing them into the open means that the makers of OpenOffice and other alternatives will have a legal way of properly supporting these formats — and that they will probably get a lot of user pressure to implement this support.

This move also seems to support a statement I’ve made some time ago: that opening up is the only way for Microsoft to retain their market dominance in the long term.

Having the binary document formats “locked up” by Microsoft gave OpenOffice.org an easy way to tell their users: “Do not save your files as .doc, .xls, and .ppt, but go with the standards-based open file formats instead.” Well, by opening up the formats the Borg has taken this excuse — and one very strong argument in favour of supporting the OpenDocument standards — away from its competitors.