World of Warcraft has lost nearly 600,000 subscribers since October 2010, Kotaku just reported, shrinking its base from 12 million to 11.4 million. This brings WoW back to numbers it had in 2009. To mix my metaphors, World of Warcraft is entrenched in a deep plateau. By extension, so are 3D online worlds in general, which just aren't reaching these millions of numbers in the West. (Half of WoW's userbase is in Asia, a considerably different market.)
While Warcraft is still an unambiguous success, and will likely be profitable for years, it's time for Blizzard to acknowledge a hard reality: The subscription-based model has been tapped out, and they need to experiment with selling World of Warcraft as a free-to-play offering monetized with virtual goods. (At least for selected content.)
Free-to-play has been consistently successful, and has worked wonders with smaller 3D MMOs. When I recently interviewed Turbine for a Social Times Pro report on virtual goods in MMOs, they told me that Lord of the Rings Online has become more lucrative since dropping the subscription requirement, and going free-to-play. (And LOTRO still has a premium subscription option, it's just no longer a mandatory one, a model WoW could easily follow.)
If Blizzard was to add a free-to-play option, they'd likely break the growth plateau, add more paying users, and organically grow the audience they can market their next MMO or WoW expansion to. That would also grow the total market for 3D online worlds, a good thing for the industry in general, and my main concern. Or they can just keep holding onto an outdated revenue model for as long as possible, like other online world companies I could mention. But right now, only Blizzard can convince the broader marketplace that 3D MMOs are a growth industry in the West -- and not one that seems to plateau at around 6 million.