The document summarizes a meetup about dark data. It defines dark data as data that is collected and stored by organizations but not used for insights or decision making. Examples of typical dark data sources are log files, customer information, previous employee data, and old documents. Reasons why dark data grows include legal risks, lost opportunities, and open-ended exposure. Estimates suggest 80-90% of organizational data is dark. Tips to manage dark data include implementing data governance, ongoing data assessment, retention policies, and specifically auditing dark data for security.