Dark data is the information companies collect but never use. It can be 60-80%...

https://magic-wiki.win/index.php/148_How_Do_I_Explain_Dark_Data_to_a_CFO_Without_Boring

Dark data is the information companies collect but never use. It can be 60-80% of their stored data, taking up space and costing money to manage. This unused data creates risks and slows down systems