Say something on Facebook and all of your friends see it. If anyone else comments on it then all of their friends may see it. So each comment may multiple the viewership of the conversation by hundreds or thousands of people.
Yes, facebook is a chainmail system, akin to ponzy scheme networking machine
Privacy options can control who can see what. It can be tailored to a very detailed viewership if desired.
I have never signed up for FakeBook. I’m convinced it will eventually be a gold-mine for the Antichrist.
But, then again, that may just be a nut-job conspiracy.