Massively multiplayer games (MMOs) are immersive virtual three-dimensional fantasy worlds in which people cooperate and compete with each other, as well as with the computer-generated denizens of that particular game world. Although typically seen as games, their strong social aspect suggests that they are a form of online communication tool, with which players interact to form friendships, create communities, and work together to accomplish a variety of goals. After an introduction to MMOs, this review explores how social aspects of the game imitate the real world in terms of choices that players make when interacting with others. Furthermore, player-to-player interactions are examined in terms of in-game group formation and how efficient communication is imperative for goal achievement. The review also explores how leadership skills learned in-game may be transferred to real-world scenarios. The reasons why people play MMOs are examined in terms of player motivations and how aspects of game play may have both positive and negative consequences for a player's well-being. The latter half of the review describes how MMOs are used as afterschool virtual teaching environments where students can use aspects of game play to learn, for example, leadership qualities. The review concludes with recommendations for using MMOs as virtual laboratories to explore aspects of human behavior.