World of Warcraft, abbreviated WoW, is a computer role-playing game (MMORPG) playable over the Internet by the US game developer Blizzard Entertainment. It was first released in 2004, in Europe in 2005, and later in other countries, including the People's Republic of China. World of Warcraft received the Guinness World Record for the most popular multiplayer online role-playing game in 2009. By July 2012, the game had generated over ten billion US dollars in sales, making it the most successful computer game. In order to play World of Warcraft, a monthly fee must be paid. There is also a free "Starter Edition" that comes with restrictions.