If you use TortoiseSvn(a popular subversion frontend that integrates into explorer), you might be interested in xdocdiff. This tool can be plugged in as a diff viewer for several binary file formats, including .doc .pdf .ppt and .xls. It works by converting both revisions of a file to txt and then using the regular diff viewer to show what has changed. I’ve been using subversion for document management for some time now. It is really easy to set up (there’s several ways actually) and really useful when working on a rapidly evolving document. Now with the ability to examine changes between revisions, it is even more useful!