Dark data is the information companies collect but rarely use—often 60% to 80%...

https://zulu-wiki.win/index.php/How_Do_I_Separate_High-Value_Files_from_Junk_Before_AI_Ingestion%3F

Dark data is the information companies collect but rarely use—often 60% to 80% of stored files. This inactive data eats up storage costs, creates security risks, and clutters AI projects with irrelevant noise