Dark data is all the information companies collect but don’t actively use—often...

https://shanesexpertword.fotosdefrases.com/what-is-the-point-of-regex-patterns-for-data-governance

Dark data is all the information companies collect but don’t actively use—often 60-80% of stored data sits inactive. It matters because holding onto this unused data wastes space and can cost businesses millions yearly, sometimes up to $2.5 million