Did you know that Richard Dawkins created the word "meme?" That famous atheist is not entirely to thank for all of the funny images we proliferate on a daily basis. In fact, his definition is nearly unrecognizable from what I understand a meme to be. According to Wikipedia, this is what a meme is:
A meme is an idea, behavior, or style that spreads by means of imitation from person to person within a culture and often carries symbolic meaning representing a particular phenomenon or theme. A meme acts as a unit for carrying cultural ideas, symbols, or practices, that can be transmitted from one mind to another through writing, speech, gestures, rituals, or other imitable phenomena with a mimicked theme. Supporters of the concept regard memes as cultural analogues to genes in that they self-replicate, mutate, and respond to selective pressures
If that doesn't perfectly define internet memes, I don't know what does! If you want to see some ideas that have spread from person to person that have meaning, all you need to do is scroll down.