Now that Sun Myung Moon is dead , and his following (certainly in the US) in precipitous decline, I have to ask: Has the era of the Internet and social media done in the old mega-cults?
There used to be a bunch of them, many with links to San Francisco. Jim Jones and the People's Temple,  of course. And anyone remember the Rajneeshees ? Among my faves; the Bhagwan had all these Rolls Royces that he drove around Antelope, Oregon (renamed Rajneeshpuram) every afternoon. Plenty of free love for all (which, after the AIDS pandemic, the Bhagwan started calling "free glove"). They had an awesome newspaper, the Rajneesh Times, run by some serious pro journalists who up and joined the cult.
When I moved out here in the early 1980s we had plenty of Krishnas , but you don't see them around much any more (a decade or so ago, they were arming themselves for some horror that was going to happen but didn't.) Religion? Cult? People call it both ways, and I'm not going to get into that fight.
I can't refer to Scientology as a cult or the group's lawyer will contact me, but you can draw your own conclusions.
But think about it: Most operations of that nature (as well as some established religions, organizations and businesses) succeed by withholding information; the initiates don't get the full story until they've been around a long time, and presumably can be trusted. But there ain't no secrets any more; you can find everything you want about Scientology or the Mormon Church or the Masons on the web.
They also tend to prey on the isolated and insecure -- and maybe the best thing about Facebook is that not so many kids in small towns are as isolated.
Is that why the likes of Rev. Moon are a dying (excuse me) breed?