A meme is a the smallest meaningful unit of information with in the context of a given culture. The term was was developed most notably by Richard Dawkins the mid 1970s. The term is derived from the word gene which is a unit of hereditary biologic information. Dawkins proposed the idea that social information could change and propagate through a culture in a way similar to genes in a population of organisms.
The Internet has been a source for the creation and prorogation of what many feel are memes. On the Internet an idea can be developed and quickly acquire modifications from users around the world such that the root idea becomes the basis for multiple spin-off ideas, subsets of ideas, and other similar iterations. In this sense, a "meme" evolves, taking on a life of its own through the contributions of users of varied cultural backgrounds.
Many "memes" are humorous in nature. "All Your Base Are Belong to Us" was an early Internet "meme," and "lolcat" is a popular emergent meme. Other memes focus on potential dangers, such as cell phones causing fires at Gas pumps.
Popular Internet Memes
Either way, the goal of the "lolcat" is to be funny, self-referential, and build on previous iterations of the "lolcat" meme. Most "lolcat" images include references and liberal use of internet slang, such as "lol," etcetera.
All Your Base Are Belong to Us
"All Your Base" was a meme popular in 2001, based on a poor Japanese to English translation of the 1989 videogame "Zero Wing." It spawned a massive video, based on the meme's title catchprase, a notable translation error.
YTMND or Your The Man Now Dog is a site dedicated to images/animated gifs that load sound bites in the background that loop.