“Peer review still plays a critical role in evaluating science, but citation-based bibliometric indicators are becoming increasingly important. This chapter looks at a novel set of indicators that can complement both citation analysis and peer review. Altmetrics use indicators gathered in the real-time Social Web to provide immediate feedback about scholarly works.”
http://book.openingscience.org/vision/altmetrics/
see also
Altmetrics Collection on PLOS
http://www.ploscollections.org/article/browseIssue.action?issue=info:doi/10.1371/issue.pcol.v02.i19
and ImpactStory
