The New York Times reports on the global appeal of World of Warcraft. An unmitigated success world-wide, the article examines why the title's U.S. roots haven't stopped it from succeeding abroad. From the article:
"Perhaps more than pop music or Hollywood blockbusters, even the top video games traditionally have been limited in their appeal to the specific regional culture that produced them. For example the well-known series Grand Theft Auto, with its scenes of glamorized urban American violence, has been tremendously popular in the United States but has largely failed to resonate in Asia and in many parts of Europe. Meanwhile many Japanese games, with their distinctively cutesy anime visual style, often fall flat in North America. One of the main reasons Western software companies of all kinds have had difficulty in Asia is that piracy is still rampant across the region. Games like World of Warcraft circumvent that problem by giving the software away free and then charging for the game service, either hourly or monthly."
Keep in mind that distribution and access rates are different in Asia than they are here in the states. The majority of WoW players pay an hourly fee, and didn't have to buy the box.