Dark data is the information your business collects but never uses—often making...

https://list-wiki.win/index.php/How_Do_I_Classify_Unstructured_Data_at_Scale%3F

Dark data is the information your business collects but never uses—often making up 55% of stored data. It increases ransomware and breach risks since old data isn’t actively monitored, while also driving up costs on storage and backup