I think it's conceivable that, while these ideas on the left and right later entered all social media and even mainstream media, they originated on Tumblr and 4chan, respectively. I wonder whether one could quantify/measure it somehow.
You could probably use something like genetic tracing, if you could come up with a way of fingerprinting free text semi-reliably.
My expectation is there are probably "tell words" (i.e. not used elsewhere or for that purpose) in novel ideas, and you could likely observe these spreading over time, as the ideas carrying them did.
One of the first things groups tend to do is specialize and redefine language / create jargon.
You can find discrediting examples in the mid-2000s thread collection the internet archive recently released ("archive ten billion"): memes appear in the chanological record years before they anywhere Google knows of. But how can you know that's the real origin? Even "Know your memes" first appears in there as a /b/ catchphrase in April 2006, but you must notice that's also when the /b/ posts in the collection begin.
Edit, another example:
4chan is also known as a Mongolian basket-weaving forum, among other things: corruptions descended from the meme of referring to anime as "Chinese cartoons". An old 4chan saying, as KYM finds? No, it came from that Russian anime newsgroup, ru.anime.chainik, after its parody FAQ from 2002 was translated by users of an associated LiveJournal group and added to a since-deleted Uncyclopedia article.
Q: Что такое аниме?
A: Китайские порнографические мультфильмы.
the livejournal stuff is also still up https://ru-onime.livejournal.com/71601.html
(2005)
and Mongolian is a stand-in for mongoloid, which fell off the euphemism treadmill as a descriptor for people with Downs syndrome.
So "Mongolian basket-weaving forum" means "place for r*, useless people"
Most memes and ideas went no where but some had a chance to multiply without getting stamped out by the censors.
4chan is unique because of its combination of scale, relative lack of moderation, and relatively high anonymity. By nature, it's a place where political radicals would be able to shitpost freely en masse. 4chan was absolutely a vehicle for platforming radical politics, but the word "shitpost" is key - the average discourse on 4chan isn't at a level where ideological formulation can happen at a meaningful scale.
Memes are the only exception. 4chan memes have, on multiple occasions, turned into widely-known (and sometimes widely-misunderstood) political imagery. That imagery routinely has no clear symbolism whatsoever, and is assigned all kinds of wacky meanings depending on you ask... which is what you'd expect from 4chan, I guess.
Agreed, but to be fair, /pol/ was created with the officially stated goal of acting as a containment board. And tbh, that’s exactly what it still is to this day.
Survivorship bias, evolutionary somethings, and curation help the shit escape 4chan's confines. I can probably word that more eloquently when my brain isn't fried.
It can be made again. But whoever does it has to learn from past mistakes.
This model attracts all manner of idiocy and hatred, and it's much too easy for one provocateur to hijack the system. The result is that the site requires several containment zones like /b/ and /pol/.
However, the upshot of 4chan (or any imageboard, really) is the total lack of narcissistic incentive. If you stick to blue boards, consciously avoid the containment zones, and you ignore the provocateurs (big IFs, I know), 4chan hosts some remarkably eclectic discussion of the arts, science, and entertainment. It's really good at elevating things that are thought-provoking or avant garde, if only within the bounds of a polarizing and inaccessible platform.
If you happen to get footage of a "happening" and post it on 4chan, people will notice (and call you various slurs).
If you post it anywhere else it's liable to be deleted, or worse, ignored.