I'm sorry, but I think you're all missing the point...
As stated in the article, Blizzard is going after ancillary audiences by promoting the game in venues that are outside of their normal scope of marketing. At the same time Blizzard has been posting a drop in number and has cut an extremely expensive convention in order to focus on the development and release of new content/games. The point is, they're being smart and saving money.

Now, even if you don't have any knowledge of marketing, I'm sure you can come up with the answer. Which do you think costs more money? A cross-promotion with 7-11, a company that exists in 16 countries, or with AMPM, existing in only 12 states.

The point is, when going after a smaller market you're not expecting huge returns on investment, they're just fishing, so they're not going to spend the money to go worldwide or even nationwide. They're going to play it safe and see how it plays out. If they get a surge in numbers, we'll probably see more campaigns like this through other, larger markets.