Altmetric - tracks mentions of scholarly works on social media sites, scholarly bookmarking services and in science news outlets through several different products, here are two examples:
Altmetric Explorer - A powerful and intuitive web application that helps you see all of the attention surrounding your papers.
Altmetric Bookmarklet - A simple browser tool that lets you instantly get article level metrics for any recent paper, for free.
Impactstory - an open-source, free web-based tool that helps scientists explore and share the diverse impacts of all their research products—from traditional ones like journal articles, to emerging products like blog posts, datasets, and software.
Plum Analytics - tracks more than 20 different types of artifacts, including journal articles, books, videos, presentations, conference proceedings, datasets, source code, cases, and more.
Mendeley - is an free, online research-collaboration platform and reference manager. Mendeley's metrics include how often papers are downloaded, shared with colleagues, and commented on. Mendeley also has an altmetrics group for researchers.
Acumen - is a European research collaboration aimed at understanding the ways in which researches are evaluated by their peers and by institutions and at assessing how the science system can be improved and enchanced. This FP7 project is a cooperation amont nine European research institutes.
Impactstory--the only non-profit devoted exclusively to altmetrics--created this guide as part of our organization's mission to help researchers and librarians learn about and use altmetrics. It's written by Stacy Konkiel, an academic librarian who is also Impactstory's Director of Marketing & Research.