Dark data is the inactive or unused information stored in your systems—about...

https://www.bookmarking-jet.win/dark-data-is-info-stored-but-never-used-think-emails-old-files-or-inactive

Dark data is the inactive or unused information stored in your systems—about 60% to 80% of it just sits there. This data isn’t just taking up space; it costs money to keep and can create noise that messes up AI projects