By the file's Comments field I mean the "Comment" column that you can add in Windows Explorer (Windows7).
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xplorer² has this note about using Comments:
File comments rely on an advanced NTFS feature called “Alternate Data Streams”
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-IainB
I'm on Vista Home Premium, 32-bit, UAC On, user account, and can't see a Comments field in Windows Explorer. Total Commander mentions "NTFS file comments, MS-Office embedded comments, comments from files.bbs and descript.ion, etc. if available." Explorer comments are supposedly available by pressing Alt+Enter. On a generic .TXT file that just seems to get me the standard Properties box. On a PDF, the Properties box has an extra PDF field that says "Information on this page reflects the actual contents of the Adobe PDF file. This page may differ from other pages of this property sheet that display Information from the Windows file system." Whatever that means. I can't seem to add or change information.
One good thing about third-party solutions; they aren't dependent on the vagaries of the particular version of the OS

I am finding that the Comment field (for most files) and the Tag field (in image files) are potentially two very useful tools for increasing and storing file meta-data. I just wish they were easier to use and get into an information management database.-IainB
Agreed, and wouldn't it be nice if there were a universal standard. DESCRIPT.ION has been the closest to that for years, though it's primarily text description, whereas you seem interested in more extensive metadata.