"Library Technology Reports (vol. 51, no. 5) introduces the concept of altmetrics, including its relation to existing citation-based research metrics and to the larger academic community. Major altmetrics tools are presented and discussed, as well as social media sources that comprise the spectrum of altmetrics, and methods for evaluating new and existing metrics tools. Drawing on recent research and online resources within the field, the report outlines both the promises and major obstacles faced by the field of altmetrics. The report also explicitly explores role of libraries in altmetrics,...