From the abstract:
Altmetrics are an alternative to traditional measurement of the impact of published resources. While altmetrics are primarily used by researchers and institutions to measure the impact of scholarly publications online, they can also be used by archives to measure the impact of their diverse online holdings, including digitized and born-digital collections, digital exhibits, repository websites, and online finding aids. Furthermore, altmetrics may fill a need for user engagement assessments for cultural heritage organizations.
The article also discusses the ethical implications of using altmetrics, best practices for data collection, and offers directions for future research.