Riot Games has announced player numbers for its extremely popular League of Legends title, and they're pretty phenomenal. With over 15 million registered players, the Defense of the Ancients-style online multiplayer RTS can now brush shoulders with games like Blizzard's World of Warcraft (12 million players), Call of Duty (13 million players on Xbox Live), and The Sims (16 million copies sold), as one of the biggest PC games in history. Granted, as a free-to-play title that relies on microtransactions for revenue, League of Legends has more access to a wider audience than games driven by retail sales or subscriptions. But there's no question at all that this is a huge and exceptionally popular game.

Joystiq got to talk with CEO and co-founder of Riot Brandon Beck about today's announcement, and he says that even the company was surprised by how big LoL (as it's called in shorthand) has gotten. "The growth of the League of Legends community far exceeded our expectations," he tells us. "We are proud of the numbers we are hitting on our platform and are confident our fantastic team can continue to grow and evolve our PvP.net technology to handle even greater numbers."