Companies always turn on the spin, very true. But it's very, very, very easy to believe 1 million N.A. subscribers. There are currently more than 100 servers (more servers still being added) and avg 10,000 per server... yep, easily 1 million.
(Actually, to be more acurate, it's probably only 999,999 -- I cancelled my account

)
What's misleading is mmorpg.com trying to translate total subscribers into monthly revenue for Blizzard Entertainment. That's just a load of crap. Half of the subscribers are in China, and its an entirely different business model in that country -- Chinese WoW players do not pay the same rate. It was a contract guarantees $50 million, or something like that. I'll have to look up the link, it was from a June article I think.
EDIT2: Pretty sure Bizzard is implying "CURRENT PAYING CUSTOMERS." Not sure how you could infer otherwise.
"This brings the total population for Blizzard's critically acclaimed game, the largest MMORPG in the world, to more than four million paying customers."
How they can claim largest MMORPG in the world, I have no idea. Obviously, someone's ignoring China when they make a ludicrous statement like that. So if they're BSing about one thing, maybe they're spreading the manure on the other?
EDIT: Found the info.
First, some numbers. In June (just before WoW release) there were apparently 100-140 million online subscribers in China, including 20 million subscribers for Legend2 (which charges an equivalent of $4 per month).
WoW China beta signed up 2+ million accounts, and had more than 500k on-line concurrently during beta.
Back in 2004, The9 (9city?) committed $74.1m to Bizzard/Vivendi.
First, they paid an initial non-refundable licence fee of $3 million to Vivendi Universal in February 2005. The9 also guaranteed approximately $51.3m in royalties, consisting of quarterly payments from $1.6m to $3.7m over a four year period. The company further promised to spend $13m for marketing and promotions of WoW, apart from $6.8m for pre-launch events.
Vivendi will receive
22 per cent of the face value of sold WoW China pre-paid cards sold as royalties.
In China, 9city is selling game time (by the score), instead of selling subscriptions by the month.
Chinese gamers purchase cards for ($3.64) worth "600 scores". Nine scores are worth one hour of gameplay, so each card is worth 66 hours 40 minutes.
Still, 4,000,000 subscribers sounds impressive, doesn't it.