Although there are a number of sources of altmetrics, there is no one platform that provides the entire universe of altmetric data. Some open access examples include: Research Gate, Academia.edu, Impactstory & PLOS; social media platforms such as Facebook, Twitter, Google+ & LinkedIn; bibliographic management tools such as Mendeley & Zotero; and services such as Figshare & Slideshare. Commercial, fee-based services such as Altmetric.com, PlumX (Plum Analytics), Digital Measures, InCites & Pure also are available.