The Canadian Association of Research Libraries (CARL) has released Altmetrics in Context.
Here's an excerpt from the announcement:
As scholarly communication takes on new forms and moves increasingly to digital and open access venues, the value of new types of metrics is increasingly important for the research community. It is causing discussion and, in some camps, heated debate.
Altmetrics report the impact of a wide range of research outputs, including data sets, articles and code. This document, available on the CARL Website, provides a quick introduction to this new field of research impact assessment and encourages researchers to use altmetrics in their work.
Want more information on altmetrics? Try the Altmetrics Bibliography.