The format of a digital object must be known in order to interpret the information content of that object properly. Strong format typing is therefore fundamental to the effective use, interchange, and preservation of all digitally-encoded content. In terms of the OAIS reference model, format typing is a component of an object's representation information. Formats themselves also have representation information--primarily, the set of syntactic and semantic rules for encoding content into digital form--that must be preserved to address the concern raised by the Library of Congress's recent planning report, Preserving Our Digital Heritage: "Longevity of digital data and the ability to read those data in the future depend upon standards for encoding and describing, but standards change over time." The Andrew W. Mellon Foundation has funded an effort by the Harvard University Library to create a Global Digital Format Registry (GDFR) that will provide preservation practitioners with sustainable services to store, discover, and deliver representation information about digital formats. This presentation will provide an update on GDFR project activities.