Subscriptions and virtual-world populations are a frequent topic of discussion in game studies, but the facts are notoriously hard to come by, since population density — often perceived as an index of popularity — is a selling point, and therefore subject to spin. Blizzard is generally regarded as one of the most forthcoming and transparent of the online gaming services, as their definition of “subscriber” refers clearly to members who pay a monthly fee:

World of Warcraft subscribers include individuals who have paid a subscription fee or have an active prepaid card to play World of Warcraft, as well as those who have purchased the game and are within their free month of access. Internet Game Room players who have accessed the game over the last thirty days are also counted as subscribers. The above definition excludes all players under free promotional subscriptions, expired or cancelled subscriptions, and expired prepaid cards. Subscribers in licensees’ territories are defined along the same rules.

This differs substantially from online services like Second Life or MMORPG competitors like Atlantica (which calls itself “#1 ranked”): While SL and Atlantica boast many million “subscribers,” their definition of a subscriber includes those who sign up for free (and may never even have subsequently returned to the site). Blizzard’s pricey subscription may be the source of much complaint, but that cost guarantees the relative equivalence of subscriber base and shard population.

I’d like to research this further, but for the moment, the math on WoW is sufficiently interesting. If, as of Dec 28, 2008, there are 11.5 million subscribers, and approximately 236 known shards (“realms” or game instances, probably equivalent to physical servers), then there is a mean of roughly 48,700 subscribers per server. One difficulty with this number: I’ve no way of knowing how many avatars each subscriber maintains: I have 3 characters on Thrall, 2 on Crushridge, and 2 on The Underbog; based on anecdotal evidence, I doubt that my arrangement is atypical. Consequently, that 48.7k subscribers/shard mean fails to reflect the reality of individuals who play across several servers.