Having been involved with a government archival project, I can say that format longevity is a serious concern.
Particularly in the case of governments, documents may be required to be archived for hundreds of years. Indeed, many local, state, national and international governments are actively in the process of establishing policies that every document must be easily retrievable using standardized formats.
Microsoft 'Frees' Office Formats (InternetNews.com)
The only thing that I'm disappointed about is that the project's in SourceForge, not CodePlex. Hrm.