Holy cow, I wrote a book!
In Windows 2000 and Windows XP,
you could add Summary information on the
Details property page to files of all types.
Text files, image files, some crazy file your grandmother sent you
in a file format you don't know how to open.
If Windows supports storing the Summary information in the file itself
(for example, in EXIF tags or in
Structure Storage properties),
then the information gets stored there.
Otherwise, Windows stashes the information in an alternate data stream.
Windows Vista dropped support for storing Summary information in
alternate data streams.
Support for storing Summary information in an alternate data stream
was dropped in Windows Vista
because alternate data streams were found to be too fragile.
If you back up the file to a CD-ROM or email it to a friend
or copy it to a thumb drive or upload it to a Web site
or store it in a ZIP file,
the alternate data stream ends up lost.
It was determined that it was better simple not to allow users
to create data that was so easy to destroy accidentally.