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. What happened?
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.