Research libraries assist scholars in demonstrating the value of their scholarly output through citation metrics and other measures. As the forms of scholarly communication change, so do the metrics used for assessing them. The services libraries offer must evolve in concert with these changes. This talk will provide a general overview of the ways in which altmetrics complement traditional citation metrics and will explore how libraries can benefit from engaging with a broader set of metrics to reach a wide range of users. The talk will cover the roles librarians can play in helping researchers and institutions understand the benefits and limitations of these metrics and will discuss how altmetrics are being used in library discovery services, how they are represented in institutional repositories, and they can drive collection development and other library decisions.