Altmetrics is the use and study of non-traditional ways of measuring impact that are based not only on citation counts, but also on web-based activity. They are the 'alternative' methods to traditional bibliometrics used by academics to measure impact factors.
Online Tools for Measuring Altmetrics
Some social media platforms can provide altmetric data as well (such as Google Scholar) but here are some emerging tools for measuring impact. The resources below require a paid subscription.