The PDF file format is an interesting example of how a supposedly proprietary standard can REMAIN a standard. There are two clear examples of proprietary standards that for all intents and purposes will NEVER be replaced by a technically better and open source one. * Adobe's PDF format can be displayed without breaking copyright because of the open source Ghostscript program. Remember the format is technically not data but program code. * MP3 music files can now be decrypted and encrypted with reverse engineered open source codecs. There have been other formats that could replace them but none of them offer any real advantages to the user. Microsoft's Windows 7 has an inferior alternative print to XPS to a PDF printer and a hard core open source advocate may prefer to rip a CD to an open source format. That he can't play on any hardware device. Even a hard core open source advocate who absolutely refuses to use the Microsoft document format is likely to have both software and hardware that uses the supposedly proprietary JPG MP3 and PDF formats in his digital camera music player and e-book reader. The e-book reader is a clear example of how the PDF format could be improved but does not HAVE to be. The e-book formats are better designed to display ALL font resolutions. This can be seen when you try to view a PDF on a smartphone with a small screen. However once you increase the screen size up to tablet it is very hard to find a PDF document that does not display properly - and the latest viewers can incorporate animations high resolution color images web s and the ability to edit the document directly. The basic idea of a portable document format * that you can view on a tablet almost as well as an e-book format - AND * that prints out EXACTLY as you see it on screen is still valid. Even if PDF is replaced by an e-book format that can do both I don't see it bing obsolete yet * when so many e-documents today are in PDF format and * when we still don't have an obvious e-book format that we can print to from ourputer where we can choose how the page resolution is decided when it is displayed - and what gets left out if there are any problems in doing this