Dark data is the information businesses collect but never use—often making up...

https://fast-wiki.win/index.php/How_Do_I_Stop_Dark_Data_From_Coming_Back_After_Cleanup%3F

Dark data is the information businesses collect but never use—often making up 60-80% of their stored data. This hidden clutter can cost companies millions, with some wasting up to $2.5 million yearly on storing and managing it