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.
For a good overview read the following article:
Rise of 'Altmetrics' Revives Questions About How to Measure Impact of Research Chronicle of Higher Education (June 3, 2013)
Researchers have found a link between scientists' public engagement and citation rates. See Building Buzz (Scientists) Communicating Science in New Media Environments published in Journalism & Mass Communications Quarterly (2014) for details.