The Cult Awareness Network was a non-profit organisation which was founded following the 1978 Jonestown massacre and existed until the mid-1990s. CAN’s main activity involved advising concerned friends and families, and the legal system on the activities of groups considered cults.
Over the years CAN attracted a number of enemies, the most prominent being Landmark Forum (successor of est) and the Church of Scientology. Landmark lauched a lengthy lawsuit against CAN; the Church of Scientology, for its part, instructed its members to join CAN en-masse (ala their attempted infiltration of the National Institute of Mental Health in the 60s and 70s). When this was identified and their applications refused, the rejected Scientologists launched dozens of lawsuits against CAN alleging religious discrimination. The CoS also funded a previously unsuccessful complaint against CAN from a member of a Pentecostal group regarded by CAN as a cult.
Under the weight of this legal pressure, CAN eventually folded, filing for bankruptcy in 1996. Their assets were purchased by a Scientologist and the organisation reformed. The two incarnations are usually referred to as Old CAN and New CAN. The new CAN is effectively a Scientology front group, attacking anti-cult campaigners and providing Scientology’s unique perspective on cult-related issues (such as their conspiracy theory that psychiatrists were responsible for the notorious AUM terrorist attack.)
In this video, 60 Minutes investigates the history of the Cult Awareness Network, and interviews people from different sides in the conflict.
(Higher quality version here).