World of Warcraft
World of Warcraft is the popular massively multiplayer online role-playing game created and developed by Blizzard Entertainment. The game was first released on November 23, 2004 in Australia and North America. Blizzard Entertainment claims that 10 million subscribers who actively play the game. The game first expansion is The Burning Crusade and it was released on January 16, 2007. Wrath of the Lich King is the second big expansion patch and it was introduced on November 13, 2008. Later, Blizzard Entertainment released the third expansion named Cataclysm on December 7, 2010. Recently, the company announced the fourth expansion set named Mists of Pandaria at BlizzCon in October 2010. The game is a big universal that let players interact with each other to kill monster and do quests. Blizzard tried and success to integrate a social network feature that let players stay connected with their real friends to complete many objectives in the game.