Another reason for "open" document formats
WIRED Blogs: Epicenter And you discover that while Google has been arguably the most successful company in the world for the past four years, it is deeply paranoid. The "risk factors" section of any 10k is typically boilerplate but Google found a way to make it interesting - coming up with 36 of them including some like this: "A large amount of information on the Internet is provided in proprietary document formats such as Microsoft Word. The providers of the software application used to create these documents could engineer the document format to prevent or interfere with our ability to access the document contents with our search technology. This would mean that the document contents would not be included in our search results even if the contents were directly relevant to a search. The software providers may also seek to require us to pay them royalties in exchange for giving us the ability to search documents in their format. If the software provider also competes with us in the search business, they may give their search technology a preferential ability to search documents in their proprietary format. Any of these results could harm our brand and our operating results."
An obvious possibility - Microsoft could assert patent on aspect of their proprietary formats, and try to prevent competitors from reading documents in that format. Not something they are likely to do while the Oasis battle of standard document formats in ongoing. Not likely if they lose the battle, and ODF becomes the standard. But if they by some measure "win" the battle - asserting patents becomes a possibility.
One more reason to support open and standardized formats for "office" documents.