I'm not an 8chan user, in fact, I am not a fan of the
chans.
I'm also not a fan of Twitter, and for similar underlying reasons.
On the chans it feels like everything is a joke of a joke, you're not 100% able to tell if someone is saying something intentionally stupid/rude to elicit a response. Coupled with the anonymous nature of the platform, and you can assume that it's one or two people trolling a thread and put it out of your mind. Because of that, you end up with the contra of mainstream opinion. And, yeah, it might have the ability to galvanise and individual (both for and against the rhetoric, because many people reject, powerfully, that kind of rhetoric and become champions of the other side).
I find the exact opposite is true of twitter. Instead of assuming it's one or two people who are trolling with the extreme of a mainstream opinion, it's -obviously- a mob, many people with verified badges are quick to jump on people for "wrongthink" and are exceedingly happy to extol their virtues and denounce the non-virtuous. Often they get so reinforced by their following that they become cancerous to the cause and have the same effect as the 4channers and 8channers (causing people to be galvanised for, and against their cause).
I see twitter and 4/8chan as two sides of the same coin, causing division in society.