Here's an interesting article about how the idea of memes, which Dawkins introduced as a metaphor in 1976, had become a raging conceptual pest by the turn of the century (full text is downloadable):
Jeremy Trevelyan Burman. The misunderstanding of memes: Biography of an unscientific object, 1976–1999. Perspectives on Science. Spring 2012, Vol. 20, No. 1, Pages 75-104Posted Online January 19, 2012.(doi:10.1162/POSC_a_00057)© 2012 by The Massachusetts Institute of Technology
Abstract: When the “meme” was introduced in 1976, it was as a metaphor intended to illuminate an evolutionary argument. By the late-1980s, however, we see from its use in major US newspapers that this original meaning had become obscured. The meme became a virus of the mind. (In the UK, this occurred slightly later.) It is also now clear that this becoming involved complex sustained interactions between scholars, journalists, and the letter-writing public. We must therefore read the “meme” through lenses provided by its popularization. The results are in turn suggestive of the processes of meaning-construction in scholarly communication more generally.