In this paper, we have propose that the Socio-Technical Interaction Network model is a useful approach to take for studying digital libraries, To extend the model to incorporate the necessity of bringing people into the STIN, the concept of enrollment strategies is suggested. Three different types of enrollment strategies are described that differ according to the kinds of interaction they require. The STIN model is then used to analyze the Library of Congress' American Memory Project which, by many measures, is a successful digital library. Three examples of enrollment strategies used in the American Memory Project ar described.