"Altmetrics" refers to alternative ways of assessing the impact of authors and publications, usually by including their contributions and mentions in social media (e.g., blogs, Twitter).
Scopus includes some altmetric information through their Altmetric app. The other tools described on this page are independent of existing databases, though some, like PLoS, are publisher-specific.
ImpactStory creates a personal altmetrics report, based on the citations you claim in your ImpactStory profile. This report is based on citations, bookmarks, downloads, tweets, and other mention of your citations. You can also create an embeddable widget of your impact report.
The Public Library of Science (PLoS) provides metrics for every article published in a PLoS publication. These metrics include amount of times the article has been viewed, cited, downloaded, saved, or discussed through sites like Facebook and Twitter.