Conventionally, science data centers are supply driven - what they do and how they do it are determined entirely by what data sets they hold. The DAAC was no different. Between 1994 and 1997, the DAAC reinvented itself by re-examining its customers, changing the focus from supply driven to demand driven and achieved breakthrough results. This is the 'business model' for science data centers. This article describes the DAAC's business model and the supply-driven data management practices.