The term for self-replicating ideas or bits of behavior that move through time and space without continuing support from their original source, such as the "keep calm and carry on" poster, is:

This term would be meme. A meme is a style, behavior or idea that can spread from person to person inside of culture generally with the idea of conveying a certain phenomenon, meaning, or theme. Often times they are funny, satirical and entertaining.

This type of self-replicating idea is called memes

memes became a massive culture all across the Glove since the development of the internet.

By using memes, all people could create a certain news, opinion, or even simple jokes in a much more interesting way