I found this on Gamespot an article talking about World of Warcraft's sub rise.
I think they explained it well, like a 9 year old game still being able to grow this big, kinda big deal. don't you think?
Blizzard Entertainment's MMORPG World of Warcraft ended 2013 with 7.8 million paying members, which is up from the 7.6 million figure announced in November. That's right, more than 9 years after release, the game is actually continuing to grow.
Of course, 7.8 million is down from a milestone of more than 12 million subscribers achieved in 2010 following the release of the Wrath of the Lich King expansion. All the same, it's impressive that the game has been able to not only stem subscriber attrition, but actually grow this late in a product lifecycle.
World of Warcraft's fifth expansion, Warlords of Draenor, was announced during BlizzCon in November and is expected to launch later this year. The subscriber numbers were announced as part of Activision Blizzard's latest earnings report today detailing fourth-quarter and full-year sales.