March 31st, 2010, is “Document Freedom Day (DFD), a global day for document liberation”. Local events have been organized all over the world to “educate the public about the importance of Free Document Formats and Open Standards in general”. Indeed, Free as in Freedom file formats are essential in a world that depends so much on digital technology as ours: they are necessary to preserve our culture, our memory, our data and lots of our public money.