Author platforms like Google Scholar, HeinOnline, and SSRN provide engagement and impact data such as citations, downloads, and more. The library takes "snapshots" of this data and can provide reports for you throughout the year. While the data on these platforms is not always complete, it can provide a starting point for engaging with the impact of your work.
TAMU University Libraries provides access to the Digital Science Altmetrics Platform, which can help keep track of social media activity, mentions, and other engagement across a variety of sources:
PlumX metrics count five separate categories: citations, usage, captures, mentions, and social media. PlumX data is integrated into Bepress author profiles and SSRN.
Citations – traditional citation indexes, as well as citations that help indicate societal impact such as Clinical or Policy Citations.
Usage – signals that someone read the article or otherwise used the research. Usage is the number one statistic researchers want to know after citations (e.g., clicks, downloads, views, library holdings, video plays). 
Captures – shows that someone wants to come back to the work, possibly indicating future citations (e.g., bookmarks, code forks, favorites, readers, watchers )
Mentions – measures references to the article in news articles or blog posts. Mentions is a way to tell that people are engaging with the research (e.g., blog posts, comments, reviews, Wikipedia references, news media.
Social media - includes the tweets, Facebook likes, etc. that reference the research; i.e., “buzz” and promotion.