Truly, what is the most autistic thing ever? Is it My Little Pony? Is it elaborate power fantasies? Is it Kiwi Farms? Is it short, needlessly 'deep' thread starters that reek of being written at a Starbucks?
Twitter... Twitter is the most autistic thing ever created by humans. The stunted word count essentially forces everyone to communicate in short, incoherent bursts of butchered up language which are almost universally misunderstood. This in turn leading to even more spastic response tweets bitching and belly aching about the original tweet. It winds up devolving into an incoherent mess of histrionic slang speak cascading all over itself into a endlessly circling cycle of completely useless, largely incomprehensible, shit pile of human communication.
If not counting this thread, then 4chan's /co/ was the most autistic thing I could think of 3 or 4 years ago. All of the worst lolcows, fandoms, manchildren, tumblrtards, spergs and neckbeards have been spawned by /co/, are connected by /co/ or behave exactly like your average /co/ poster, right down to behaving like children or wanting to fuck animated little girls who want to sit in the back seat of cars. Even the worst /b/ had to offer were usually anons who had been banned from /co/, like /b/ronies. Bronies were probably the pinnacle embodiment of everything wrong with /co/ and the internet as a whole, and they would eventually lead to the spawning of even worse fandoms and communities.
Nowadays there's just too many horribly autistic things coming from every corner of the net (especially Twitter) to keep track of. So I guess the internet as a whole is the most autistic thing ever.