Dark data is all the information companies collect but never use—think 60-80%...

https://romeo-wiki.win/index.php/What_is_KAPPA_Data_Services_and_What_Can_It_Extract%3F

Dark data is all the information companies collect but never use—think 60-80% of stored data just sitting idle. It matters because this inactive data wastes storage space and can cost businesses up to $2.5 million every year in unnecessary expenses