World of Warcraft has entered its 21st year in operation, which makes it a true rarity within its genre, and potentially within the industry in general. It remains the world's most popular subscription-based MMORPG, with millions of players funding large ongoing story and PvE content drops every few months, with large world-growing expansions every 1.5 years or so.
WoW has enjoyed something of a renaissance recently. The "current" retail version of the game has received what may end up being remembered as one of its best expansions ever, with The War Within.
