All advertising is (intended to be) mind control. It wants to get you to take an action you weren't previously inclined to take.

It follows that any product that's successful at controlling people can sell that control.

If you consider the implications of Facebook-as-mass-mind-control, then Russian election-meddling, viral suicides, and all of Facebook's other facets make a lot of sense.

It also makes sense that Facebook wants to get better at controlling you by learning more about what motivates you, leveraging social pressure, and taking over more of your attention.

(That said, I still enjoy and use Facebook. I'm just worried about how powerful it is.)