Dark data is the vast amount of information companies collect but never use —...

https://wiki-dale.win/index.php/What_Is_KAPPA_Data_Services_and_What_Can_It_Extract%3F

Dark data is the vast amount of information companies collect but never use — around 60-80% of it just sits inactive. This unused data takes up storage, slows down systems, and can cost businesses an average of $2.5 million each year