Dark data is the information companies collect but never use—up to 80% of data...

https://www.toro-bookmarks.win/dark-data-is-the-info-companies-keep-but-never-use-think-old-emails-documents

Dark data is the information companies collect but never use—up to 80% of data sits idle and hidden. This unused data can cost businesses millions each year, often around $2.5 million wasted on storage and management