The idea is to stop people posting the first thing that pops into their head: hopefully taking more time to formulate a response (or reconsidering if it was valuable to say anything at all).
So if we can detect you said something about climate change, you see a little popup asking you if water boils at 100 degrees Celsius or Fahrenheit? If you don't get it right, you are no longer allowed to post or reply to climate change topics.
Did you just say Trump was the BEST or WORST President in History? I'd like to see if you can name 5 Presidents before 1980? If not, I don't think we need your opinions on historical ranking.
The tests wouldn't be hard. And they would easily be Googleable, but there would be 10 second time limit for them to be completed.
It would probably be the least popular social media company ever created. This is also a terrible idea, because the users that are entitled to post, probably would not be humble and might be jerks.