Remember all the K pop twitter hash tag raids, and the massive influx of fake anonymous accounts on twitter.
At the start is was mostly younger GenX and millennials. Most came from halfchan, what I found odd was it seemed like a bunch of old halfies showed back up that for there reasons had been away for year, it is almost like some invisible beacon went off. No way for me to sauce this, but I learned of half chan while I was in the Mil in 2008.