Meme
A unit of culture that spreads through copying and variation. The term was coined by Richard Dawkins in The Selfish Gene (1976) as a deliberate analogy to the gene — the internet meme is the special case everyone now means.
What makes a format a meme isn't the content but that it's a template: an image macro, a video edit or a sentence structure others can fill with their own and which requires recognizing the original. Spread rewards variations that are easy to make and satisfying to recognize, which is in practice exactly the evolutionary model Dawkins described. Lifespans have shortened drastically: a format that once lived for months now burns out in days as platform recommendation feeds saturate the audience. Know Your Meme is the established documentation. It's now used as much in marketing and political communication as for fun.