Memetics, after "genetics" and "même" (French for "memory"--the mistaken pronunciation "Me! Me!" is appropriate but apparently coincidental), is a term coined by Richard Dawkins in his book The Selfish Gene, describing the flow, transfer, or spread of ideas as a process of generation based on the "highjacking" of higher organisms in a process similar to viral self-replication. Any idea, phrase, thought, or trope can be viewed as a meme; those that spread, that has implicit in their paradigm the ability and need to spread, are the most "evolutionarily" successful. Memes compete against one another in a Darwinian struggle for replication; spreading quickly or eliminating competitors help a meme to survice. Examples of memes might include evangelical Christianity, the Roman alphabet, the English language, or "Eleanor Rigby" by the Beatles.
The idea has been seized upon by a number of science fiction (notably Samuel R. Delany and, later, a number of the cyberpunks, notably Bruce Sterling) & avant-garde (notably but not exclusively William S. Burroughs) writers. Memetics has also received considerable attention on the Internet, which itself can be viewed as an example of a meme. In fact, the theory of the meme can itself be viewed as a meme (and it is proving to be a fairly succesful one).
To quote a .sig I've seen on alt.memetics:
|Inf(l)ections by Steve Cook|