If I had to pinpoint one specific time period it would be 2015. That year had a ton of digestible, American-style shows that ushered in legions of people that didn't like, care for or respect the medium (or subsection of the medium, whatever), they just liked Japanese meme cartoons and making stupid Twitter jokes. In one fell swoop, the board went from a place to discuss every facet of anime and manga to "le epic meme zone - top 10 anime fights! LOL!!".