Dark data is the information your company collects but never uses—think of it...

https://web-wiki.win/index.php/What_is_Data_Curation_and_How_is_it_Different_from_Data_Classification%3F

Dark data is the information your company collects but never uses—think of it as digital clutter. Around 60-80% of data sits inactive, taking up space and costing businesses up to $2.5 million each year in storage and management