Steven Aftergood writes on fas.org:
The Chinese Communist Party employs a growing network of student informants who monitor political expression on university campuses and denounce professors and students for politically subversive or unconventional views, according to a recent report (pdf) from the Central Intelligence Agency.
Established in 1989 after the Tienanmen Square protests, “the principal objective of the Student Informant System [SIS] is to ensure campus stability and to control the debate and discussion of politically sensitive issues,” the CIA report said. “Students have had their scholarships revoked and their academic records penalized because of information provided by student informants that is sometimes highly subjective, such as facial expressions.”