Big data refers to large amounts of diverse data that are growing exponentially due to increased digital activity. Shared data connects these disparate sources of information through linking related data points. This allows data to be reused, corrected efficiently, and shared in potentially useful ways. For libraries, big data could include patron records, bibliographic data, and more. Linked data in particular supports library goals by making information reusable, correctable, and shareable across systems through relationships between data. However, privacy and potential misuse of inferences from big data are ongoing concerns that must be addressed.