I had to admit that I did not exactly know what a meme was -- I thought it referred to this particular style of graphic. As I started to investigate, I learned that a meme is similar to internet viral content, except that each user changes it as he or she copies it, adapting it to individual messages. A meme, then, is like a micro-genre or a heuristic devise that can convey a wide variety of ideas in broadly similar packaging.
I learned the distinction from the Know Your Meme web site, where I also found an interesting article about what this particular meme with a cumbersome name tells us about the way we view ourselves and the what we think about the way others view us.
I made my own version using simple cut-and-paste methods with my browser and PowerPoint (and shirking my usually scrupulous academic habits to get the photos quickly, losing the attributions in the process). A few days later I learned that this particular meme can now be spread using a simple utility at UthinkIdo.com, which now hosts my Teaching Geography graphic. (2023 UPDATE: That site is gone, but I captured the image and am reposting it now.)
This little fad has been particularly interesting for me as a geographer, because I teach two senior-level university courses -- one for geographers in general and another specifically for teachers -- in which I push students to examine what it means to be a geographer, and in particular a geography teacher. Some of the ideas in the graphic I eventually created arose from discussions with students in the teaching class (thanks!).
The meme phenomenon is certainly facilitated by internet technology, but memes circulated quickly and widely in an earlier generation via office photocopiers, as documented in When You're Up to Your Ass in Aligators (1987) by Alan Dundes and Carl Pagter. The term meme predates this work, having been introduced by biologist Richard Dawkins in 1976 in The Selfish Gene.