As for my personal experience, internet comment sections will pollute one's brain.
Filling your brain with reasonably reliable information is good, but filling it with people online just saying things isn't.
For example, when 30 reddit comments all repeat the same "fact" (for which their source is other reddit comments), it can subtly work its way into your subconscious as something you know is true but can't remember where you first heard it, which is only one step away from seeming like "common knowledge."
Now imagine a similar effect with a politically charged news story instead some random fun fact. Now imagine all the comments are actually just AI run by propagandists with the specific intention of making you believe things that aren't true.
One way I've tried to avoid the worst effects is by being very careful to remember my source for anything I know. I never say "It turns out xyz," I only say "according to abc, xyz." It's probably not enough, I think it might be time to just get off internet forums entirely.
Yes, I'm a hypocrite and yes, it's very funny.
