+- http://www.errzero.com/
+- https://www.honeybadger.io/
+- http://trackjs.com/
+- https://getcoalmine.com/ [DEAD, Nov 8, 2013]
+- http://damnit.jupiterit.com/ [DEAD]
+- http://rescuejs.com/ [DEAD, acquired by Bugsnag]
+- https://errplane.com/ [DEAD, pivoted]