Dark data refers to information assets that organizations collect and store during regular business activities but fail to analyze or use. It is a type of unstructured, untagged data found in repositories. Dark data includes log files, archives, and other data objects that have not been analyzed for business intelligence or decision making. IDC estimates that up to 90% of big data is dark data. While storing dark data incurs costs, analyzing it can also be expensive since its value is unknown. The first step to understand dark data's value is identifying what it contains, where it resides, and its status in terms of accuracy and age.