The Portal to Texas History is a gateway to humanities collections within the digital library of the University of North Texas (UNT) Libraries (http://texashistory.unt.edu). Currently, materials from more than 190 content partners are available and the number of partners continues to grow. While ever-increasing numbers of partners and assets are signs that digitally preserving and making resources Web-accessible is a desirable thing, universities, cultural heritage institutions, and funding agencies increasingly expect measurements that report the impact and value resulting from digitizing and preserving assets. Because the Portal is fairly unique in both the number and scope of its content partners, it serves as a good case study for measuring the impact of digitization for two key digital library stakeholder groups: content providers and users. This paper reports the initial findings of a study of the impact of digitizing assets, specifically: (a) a framework of impact areas and indicators, and (b) findings for the Portal's content partners and users.