Dark data is all the information companies collect but never use—think emails,...

https://stateofseo.com/what-does-agentless-really-mean-for-storage-analytics-tools/

Dark data is all the information companies collect but never use—think emails, old files, or system logs. It can make up 60-80% of stored data, costing businesses up to $2.5 million a year in storage and management fees