These are quantitative metrics which let you track how your publication is being used by readers. Citation counts are the longest established while newer metrics include “altmetrics” and “outputs in top percentiles”
Citation counts can be tracked in a number of different resources but the key multidisciplinary databases are Google Scholar, Scopus and Web of Science. The citation count for each article tracked in these databases will more than likely differ across all three because each include different publications in their databases.
Many publishers now included citation data on their platforms which they either track between their own publications or incorporate Crossref "Cited-by" data.
Altmetrics was coined as shorthand for alternative metrics and encompasses a diverse range of indicators for a digital item. The signals can include downloads, views, likes, shares, social media mentions like blogs and twitter as well as software reuse. These metrics accumulate quicker than citation metrics and are indicative of reach beyond academia.
There are currently 3 main providers of altmetric services: Altmetric.com, Plum Analytics and Impact Story. Many publishers have integrated altmetrics into their web platforms e.g. Plum Analytics is used on Scopus records so you may already be familiar with them. Altmetric.com have made available a free bookmarklet which allows you to get altmetric data for any of your publications as long as they have a DOI.
Outputs in top percentiles is a metric calculated by research analytics tools such as SciVal or InCites. UCC has a subscription to SciVal which gives the percentage of publications for an entity that fall into the top 1%, 5%, 10% or 25% of the world’s most highly cited publications in the Scopus database. Field-weighting may be applied optionally and has been set here in the screen shot for the set of publications from Ireland which are in the top 10% worldwide.