Dark data is the information your company collects but never uses—often 55% or...

https://future-wiki.win/index.php/Dark_Data_and_AI_Governance:_What_Should_Be_Blocked_from_Ingestion%3F

Dark data is the information your company collects but never uses—often 55% or more of all stored data. This unused data takes up space, drives up storage costs, and creates security risks