It always seems very odd to say "beat the game" in the same sentence as MMORPG, because one of the cardinal rules of this genre is the belief that nobody should be able to truly "beat" an MMO. It's uncertain when a rule like this was established, but if you ask any dedicated player out there, chances are high that they'd note that MMOs are designed around progression, and a viable conclusion to that progression is typically seen as bad news for the game.
What is interesting, however, lies in how the definition of "beating the game" has evolved from a simple "killing the last boss," to finishing a massive list of achievements across every aspect of World of Warcraft.
Blizzard Entertainment has announced the opening of beta registrations for “World of Warcraft: The War Within,” inviting players to explore new subterranean worlds beneath Azeroth.
Danish from eXputer: "Despite Blizzard's attempt to give a fresh new spin to World of Warcraft, some fans still seem to be stuck in the past."
HG writes: "Blizzard is usually pretty bad at keeping secrets, but the company somehow managed to keep this one under wraps until now. Plunderstorm is a special limited-time event that’s basically World of Warcraft’s take on the Battle Royale genre."