Using government agents and infiltrators with false identities to debunk conspiracy theories – the irony! The absolute irony :)
However… I don't want to throw out the baby with the bathwater. A few years ago I used to be quite vocal about my political views on Fakebook and Twitter. I got the impression that either people weren't interested or that my "political" posts weren't being seen. Now I just use Fakebook for fun interactions with friends. I take reasonable precautions – for example, if I'm mentioning a large business on Fakebook, I always asterix or misspell their name, so it doesn't add to my social profiling. If I'm filling in a "fun" survey I always put untruthful or misleading answers. I think younger people who have grown up to think social media profiling is "normal" are more at risk from manipulation.
I would say that Meetup has enriched my life enormously. I have lots of actual flesh and blood friends who I've met via that platform. I've noticed some questionable political networks springing up on Meetup, but I use it only for fun/hobbies.
As an aside, I think a Meetup-style social network would work really well on Steemit.