John Lanchester manages in a review of a number of books to extensively pin down where Facebook is, here:

John Lanchester reviews ‘The Attention Merchants’ by Tim Wu, ‘Chaos Monkeys’ by Antonio García Martínez and ‘Move Fast and Break Things’ by Jonathan Taplin · LRB 17 August 2017

Here’s some reasons why you should care, even if don’t use Facebook

• Russians are using Facebook to influence American elections (and likely other elections too)
  Mark Zuckerberg may run for President in 2020 and use the same technology then to win

Facebook has an ability to influence politics in ways that no one understands, except possibly Facebook. I don’t imagine they are going to share that information readily. Politicians need to push back on Facebook and discover the extent of their influence.

My belief is that the strength and influence of social media like Facebook is going to decline in the next few years. That’s not anywhere certain at this point, though, and the power they have needs to be limited now.