Back in the day, I had an interest in studying the various cults from a human behavior point of view. It was fascinating how they were able to attract and keep members loyal to their cause and loyal to their leader. From the Moon Unification movement, Jim Bakker and PTL, the Armstrong's (Herbert and son Garner Ted) Worldwide Church of God, to Jim Jones and Jonestown and more.
The gold standard handbook and information resource on cults at the time was Dr. Walter Martin's book Kingdom of the Cults.
As a side note, in the early days of home satellite TV, technically you needed one letter of approval from a satellite content provider granting you permission to watch their programming to make your satellite station "legal". PTL was one of the few networks that would send you a letter giving permission, so they received a large number of requests for permission letters from home satellite TV viewers (few of which probably actually watched the network) 
If I remember correctly, Dr. Gene Scott's University Network and TBN would also give you letters of permission.
People tried to recruit me into varied cults during my salad days. One was the Church of Christ. It wasn't the strict mainstream church that was "the one and only way to Heaven", and it wasn't Saint Barack's "GD America" version. It was the one based in Boston whose members were rivals of the members of the one based in New York City (just kidding after "Boston").
You don't see much of that stuff these days. You also don't see as many evangelists screaming and yelling at college students between classes on their campus. I guess that it's now classified as hate speech as well as an invasion of one's safe space. These poor kids are missing out on the joys of being called drunken heathens by angry preachers.
