According to Wikipedia, an internet meme is an activity, concept, catchphrase or piece of media which spreads, often as mimicry, from person to person via the internet. Some of them make you laugh, make you curious to think about, some carries new concepts or ideas or some points to issues and relations that normally nobody would notice or care to think about. I've been able to compose some such memes based on ideas and concepts, though some are purely imaginative.