I was stunned by the Jonestown mass suicides/murders and could never understand why - why would so many people willingly agree to kill themselves and their children. Why would they literally drink the Kool-Aid? There were signs long before Jonestown was even built that Jones was becoming mentally unstable. Look at the way his church went from welcoming strangers to frisking all who entered. The way he demanded more and more proofs that they loved him. Yet his followers stayed true to him.
Jones used the same techniques that all cult leaders and dictators use to keep power: fear of outsiders, sudden, uncalled for punishments, food and sleep deprivation, slow eroding of personal will, and encouragements to report on others. Look at how Kim Jong Il treats the people of North Korea - under constant surveillance, hungry, looking to him for validation. If we learned anything from the Jonestown tragedy, it's that we cannot give up the responsibility for our selves to anyone else, and that we have to be able to think and decide for ourselves.