Altmetrics "...is the creation and study of new metrics based on the Social Web for analyzing, and informing scholarship." Some altmetrics systems include traditional citation tools as well as media mentions. For example, this is a list of categories of metrics Plum Analytics includes:
Altmetrics attempt to assess the impact of work not only via citations in journals but through blogs, reference management systems, academic social networks, and other platforms that reflect the fact that: "In growing numbers, scholars are moving their everyday work to the web."
Citation counting, peer-review, and journal rankings are, in this view, insufficient and hence there is a need to shift toward alternative measurements of influence, impact and worth. There is also concern about the timeliness of publications, responses to these, and hence the timeliness of impact--a concern that Altmetrics attempts to address.
Altmetrics are not citation analysis tools per se, though they are related to traditional bibliometrics. "Altmetrics reflect the impact of the article itself, not its venue. Unlike citation metrics, altmetrics will track impact outside the academy, impact of influential but uncited work, and impact from sources that aren’t peer-reviewed."
Some of these Altmetrics tools are wholly or partially free of charge (depending on what you want to do) and others are commericial products that charge.
See more on ALMs from the Public Library of Science:
Although Article-level metrics are not completely new and ALMs are not strictly article-level, here is another recent definition of ALMs from SPARC:
"Article-Level Metrics (ALMs) are a new approach to quantifying the reach and impact of published research. Historically, impact has been measured at the journal level. A journal’s average number of citations to recent articles (i.e., its impact factor) has for years served as a proxy for that publication’s importance. Articles published in highly-cited journals were viewed as impactful by association. As electronic dissemination of scholarly content surpassed print, it became easier to disaggregate an individual article’s impact from the publication in which it appeared. It also became possible to track different markers of an article’s reach, beyond just citations. ALMs seek to incorporate new data sources (sometimes referred to as “altmetrics”) along with traditional measures to present a richer picture of how an individual article is being discussed, shared, and used." — Greg Tannenbaum, "Article-Level Metrics: A SPARC Primer" (2013).