Altmetrics are metrics for social media mentions and uses of scholarly output. This data can be useful for monitoring your personal impact with other scholars, practitioners, policy makers and the public.
A good overview can be seen in the article by Howard, J. (2013, June 3). Rise of 'Altmetrics' Revives Questions About How to Measure Impact of Research. Chronicle of Higher Education. Retrieved from http://chronicle.com/article/Rise-of-Altmetrics-Revives/139557/
Librarians' view about the evolution of scholarly metrics can be found in
Having your work formally cited by other researchers is a very slow process. Altmetrics (number of tweets, blog posts, likes, bookmarks, etc. in social media) are faster and wider-ranging measures of how people—both other researchers and the general public—are interested in your work.
ImpactStory offers a 30-day free trial to a $60/yr subscription tool that brings together a diverse assortment of altmetrics and traditional citation metrics for your research outputs, including both journal articles and datasets. Run a report on a particular journal article or dataset using its DOI, PubMed ID, or import your entire bibliography of articles/datasets using your ORCID (Open Researcher and Contributor ID) or a BibTeX file exported from Google Scholar.
Other similar altmetrics tools include PlumX.
Some pre-print repositories, such as the Social Sciences Research Network, provide number of views and downloads for each document.
Tool for viewing altmetric data from selected publisher websites such as Nature, Springer, Elsevier and Cambridge.