World of Warcraft (WoW) is an MMORPG created by Blizzard in 2004 based on the Warcraft series, known for having the largest player base of any MMO since 2006. WoW has had 4 expansions and a $15 monthly subscription fee that has supported the game remaining active for over 8 years, though Blizzard may eventually replace it with a new MMO called Titans that would stop WoW updates.