Broadly speaking, a meme (pronounced: “meem”) is an idea or thought (an image, quote, symbol, joke, etc.) that spreads from person to person in school, work, the media or society at large – becoming popular and easily recognizable.

In the pre-internet days, commercials with popular jingles and slogans (such as the classic “Always Coca Cola” television spot), as well as a phrases from popular TV shows and films (such as Arnold Schwarzenegger’s famous “I’ll be Back” in Terminator) can be considered memes. However, these memes were created and popularized by advertising agencies and film studios – providing a unidirectional way of communication where media companies talked and the audience listened.

In our social media era, however, memes are mostly user-generated and shared through meme sites such as Reddit, 9GAG and quickmeme, as well as through Facebook, Tumblr and Twitter. Unlike the “Always Coca Cola” days, online memes give the user power and control. He or she takes elements from popular (or unpopular) movies, TV shows and politicians to mix them into creative and hilarious pictures with quotes, jokes or statements that can go “viral” — fundamentally transforming communication between media companies and their audiences into a bidirectional process.

Following, the Top 50 Most Popular Online Memes (warning; some contain graphic language):