http://stevenpoole.net/blog/goodbye-cruel-word/

Am I not worried that WriteRoom and Scrivener, delightful though they are, are small products from tiny outfits, not “supported” by the corporate might of a large company such as Microsoft? No, I’m not. Because actually my writing is now more secure. Instead of a bloated proprietary file format like .doc, both programs use accessible formats – .txt, .xml, .rtf3 – that (as far as one can predict these things) will be readable forever. My new book is one big “project” in Scrivener, but under the hood each chapter is a universally accessible .rtf file, which can be opened and used in a multitude of other programs.