Altmetrics (alternative metrics; article-level metrics) are measures of attention or influence. Altmetrics were generated as a way to quantify the rapid spread of scholarly ideas through social media, article downloads, and other web based activities. Some altmetric indicators also factor in some citation-based data as part of their formula.
Altmetric.com provides a colorful "donut" graphic and the Altmetric Attention Score to indicate activity on the web related to a scholarly output. Download the Altmetric Explorer bookmarklet to your browser (Chrome, Firefox, or Safari). Then, whenever you pull up a journal article with a DOI and click on the bookmarklet, you will get information on citations, Facebook posts, news coverage, blogs, and more to track use and discussion of the article.
User "tagging" of author disciplines helps facilitiate cross-disciplinary impact comparisons of resarchers. Download this browser extension (Firefox or Chrome) to get crowdsourced information on an author's impact. This tool provides some interesting networking visualizations and other unique information.