Dark data is the information companies store but rarely use—up to 60%-80% of it...

https://mega-wiki.win/index.php/Why_Do_RAG_Systems_Hallucinate_with_Messy_Enterprise_Data%3F

Dark data is the information companies store but rarely use—up to 60%-80% of it sits inactive. This unused data can rack up storage costs, create security risks, and add noise that throws off AI projects