Last updated: July 7, 2017
Some of these are obvious:
Authors
Researchers
Administrators
Publishers
Librarians
Editors
Metrics analysts
And
Funders
IEEE Xplore: As of February 24th, 2016, articles published in IEEE and IET journals will include the Altmetric donut on the metrics tab of their IEEE Xplore article page. Example: http://ieeexplore.ieee.org/document/6740844/metrics
EBSCO databases and Plum Analytics. Example: MathSciNet
PLoS http://journals.plos.org/plosone/