What is a meme, and what's the history behind this word?
A Meme (short for "Memetic", meaning 'propagated idea') is an idea, behavior or style that spreads from person to person within a culture. It can include jokes, catchphrases, clothes, music, and more. They are often used as social commentary on current events or other media.

The word itself was first introduced by Richard Dawkins in his 1976 book "The Selfish Gene" but its usage really took off with the rise of Internet message boards and forums around 2000. The word has since become part of popular slang.