Don't have the time to read through this whole thread right now, but two things:
A. Why am I on Facebook? Several factors. I did resist it for a long time, but:
1. Various friends and family members were insistent that I was making it harder for them to plan events or keep in touch in the way they normally do (by forcing them to use email instead of Facebook).
2. Friends got Mom and Dad into it, and neither of them knew how to make use of the features, so they wanted me to learn and teach them.
3. My niece (12) is an avid user, and my dad was concerned that someone ought to be keeping an eye on her activities, so (basically) I got elected.
There were other factors, but those are the biggest. And yeah, it's not the sort of site tailored to my needs, any more than IMVU was. And you're right that I could play almost any other game imaginable.
On the other hand, Extra Credits
tells me to play even games not aimed at me, ones I think I wouldn't like, in order to better understand games and game theory. So there's that.
B. Communism, Socialism, Capitalism...
Told you I didn't put much thought into it.
And yeah, it definitely does sound like a Pyramid scheme. You can't get very far unless you get all of your friends to drop what they're doing and join in. (On the other hand, a circle of friends can feed off themselves in a way pyramid schemes haven't been able to do in real life. You get to pass gifts both ways, freely, because of the nature of computer-code objects as opposed to real-life money.)
Thanks for the responses; I look forward to reading the rest of them.
Only the curious have, if they live, a tale worth telling at all.