Social networks are bound by law to not reveal data requests from government organizations. But there is no rule stating that a network cannot say that they have not received a data request. In a web-based sleight-of-hand, Canary Watch uses this loophole to monitor a steady stream of postings by social networks indicating they have not received any such data request. If there is a pause in the regularity of these "no request" postings, Canary Watch gets an instant indication that a social network has been contacted by a government organization to provide information.
The service was launched by a group of non-profit organizations including the Electronic Frontier Foundation, the Berkman Center for Internet and Society, NYU's Technology Law & Policy Clinic, and the Calyx Institute.