Dark data is the information companies collect but never use—often sitting idle...

https://mag-wiki.win/index.php/What_is_Data_Curation_and_How_is_it_Different_from_Data_Classification%3F

Dark data is the information companies collect but never use—often sitting idle and forgotten. Studies show 60-80% of data falls into this category, leading to wasted storage and security risks. Ignoring dark data can cost businesses up to $2