Dark data is the inactive information companies store but rarely use. It can be...

https://www.normalbookmarks.win/dark-data-is-hidden-information-your-company-keeps-but-rarely-uses-about-55-of

Dark data is the inactive information companies store but rarely use. It can be as much as 60-80% of all stored data. This unused data takes up space and costs businesses millions—sometimes $2.5 million annually—in storage and management