Changyou.com (NASDAQ: CYOU) is a developer and operator of online games in China. It began operations in 2003 as Sohu.com's massively multi-player online games ("MMORPG") business unit, before its carve-out as a separate, stand-alone company in December 2007 and subsequent listing on the NASDAQ Global Select Market in April 2009. It engage in the development, operation and licensing of online games, including MMOGs and Web games. It also own and operate the 17173.com Website, one of the leading game information portals in China.