Meme
Before it became synonymous with pictures shared on social media, meme was a term coined by Richard Dawkins meant to refer to the way that ideas self-replicate in a way that is similar to genes or a virus. A particularly useful or entertaining idea will spread far and wide, while the vast majority will come and go without a blip on the radar.
In metaculture the term meme will refer to the Richard Dawkins definition, since this is a useful way to describe important ideas, how and why they spread.