For folks excited by the availability of the binary file format specs last week, but concerned about the long term availability of those documents, this should be good news. The British Library has archived, and now made them available to the public: http://www.bl.uk/dp/formats
From the website:
The British Library has agreed with Microsoft to archive and provide access to the specifications for the Microsoft Office binary file formats. This provides an independent guarantee that people today and in the future will have open access to these specifications. The documents listed below are covered by the Microsoft Open Specification Promise.