This is about a free and open source solution to the problem, available at
http://filemeta.codeplex.com.
I began with the same issues, for instance wanting to add comments to research papers that I had downloaded as PDFs. It has bugged me for years, until I got annoyed enough to have a closer look, and it turns out that Microsoft originally intended to provide an answer. NTFS supports the attachment of extra data to any sort of file in a sort of annex called an 'alternate stream'. And built into the file system is an API to store sets of properties in these alternate streams. Even more amazing, Windows Explorer consumes the self -same API for the display of properties as part of its extensibility model. This all dates to the Vista era, and I can quite believe that they were connected up in some beta version. The code to make the connection compiles to one 17 K 64-bit DLL. Especially sweet is that search and the indexing service consume the same API, so that you can search on any comments, tags or other properties that you add.
So why did Microsoft back off? Because, although the properties are stored as part of the file in NTFS , and so get moved around automatically with the file, the properties are lost when the file is moved outside NTFS e.g. attached to an e-mail. Microsoft probably thought this was too big a weakness, and so switched to supporting only properties held within a file format (Office documents, and many image and music file types). But I think this was throwing the baby out with the bathwater, because it meant that not all formats are supported properly or at all e.g. PDF, and text files are doomed never to have any tags, comments etc.
Having got this solution working, I thought there might be other people out there who want to be able to set properties on any file and who are prepared to cope with this limitation. So here it is! Take a look if you think it might work for you.
