Article Level Metrics (ALM) emerged from an initiative of the PLoS to provide an alternative category for the classification of articles as citable or non-citable items. Launched in 2009, ALM now provides different impact and performance indicators, collecting data of different sources: views, saves, discussions, recommendations, and citations. PLoS collected data are accessible through APIs and widgets for free download. However, these measures and data are restricted to those articles published in PLoS.
Altmetric.com has been set up in 2011 as a commercial enterprise providing social media outreach for individual researchers and publishers. Its goal is to provide its customers information about the attention a single article receives. Altmetric.com has established a composite indicator that combines different sources of data (news, videos, policy documents, Facebook, Twitter, LinkedIn, and Pinterest), resulting in a single indicator visualized by different colours which is often termed ‘altmetric donut’. The altmetric donut aims to inform about both ‘the quantity and quality of attention received by each item, applying some kind of control for gaming’.