Online games are a relatively new type of games that are gaining on popularity throughout the world. More and more people, not only children, play online games and there are millions of players right now. Approximately ten years ago online games were still almost unheard of. Very few people played them at that time. But with the bigger and bigger availability of the Internet, anyone can play online games, from almost every corner of the world including Brazil, China, Japan, and India. It looks that online games are everywhere. I welcome this interesting phenomena, and I am very glad that it is happening on my own eyes. If you are wondering what people were doing before online games were invented, we have to assume that they were either playing single player games, or even playing traditional games like chess. The reason why I am saying this is that online games attract those who like to play games in front of their computer, but also those who like to socialize with others. Some multiplayer games do not even try to add a lot of content, but they rather try to make user interactions as often as possible. According to players, an online world gives a lot of possibilities, and this is mostly due to player interactions.