If librarians want to improve their visibility and value in the increasingly crowded digital information spaces, where users expect good results without expending much time or effort, they must learn to repurpose data to create added value. Since librarians already possess valuable data sources, like circulation statistics, reference transactions, interlibrary loan requests, and usage behaviors, the next step is to utilize these data to produce useful intelligence with little effort and cost. The benefits of data mining (the process of using sophisticated data search capabilities to discover correlations in preexisting databases) often depend on the scale of the data sources from which intelligence is gathered. In this article, the authors illustrate the benefits that can be derived from using the WorldCat bibliographic database system not just for cooperative cataloging, resource sharing, and bibliographic research, but for the scope and depth of the intelligence that can be mined from it. The authors describe general areas where librarians could realize immediate benefits from using the intelligence that can be mined from WorldCat, and cite examples of the data mining projects underway in Online Computer Library Catalog (OCLC) Research.