Not Disc.
I've been dragging my feet on writing that long-promised Plagiarism Adjustment (under the draft as it stands, this would be a slap on the wrist), but I feel I have to suggest something in line with what that policy proposal will eventually say.
Meme culture is something that fits… uncomfortably and perhaps entirely inadequately under our current working definitions of plagiarism. But it's also something that influences most every internet user, including staff, often quite heavily. There is an understanding about memes that they can be copied, largely wholesale and almost always without credit, and pasted elsewhere. Indeed, that's likely… the entirety of meme culture in summation. I think it is heavily unfair to expect new users to somehow psychically decide that this is the one place on the internet that operates differently (for now, at least; again, I'm looking to change that) and, when they fail to guess that, punish them with our harshest punishment.
This is not comparable to what we want to describe as plagiarism when we use the word, which is the passing off of literary or academic works as one's own, with a necessary element of deception. This is some kid copying a meme. Does he really need anything more than a "don't do it again"?