Activision said that demand for its Call of Duty Elite subscription exceeded its own optimistic expectations. While the company hasn't revealed how many subscriptions have been purchased, we can get an idea thanks to GameStop. In a recent earnings call, the retailer announced that nearly 600,000 subscriptions were sold at their stores.

That's a staggering figure for an online service that has yet to prove itself. Even more incredible is the fact that this number only accounts for vouchers purchased at GameStop locations--undoubtedly, the figure jumps much higher when you include all subscriptions purchased directly on Xbox Live and PlayStation Network.

According to Gamasutra, the 600K sales of Call of Duty Elite makes it one of GameStop's "top 10 launches" in 2011 so far, and proves that the retailer's strategy of selling downloadable content in its stores is paying off. CEO Paul Raines said that "downloadable content is proving to be the killer app our [store] managers told us it would be."

GameStop's digital push is actually expanding the audience of downloadable content. According to the company's research, "half of the DLC we sell is to customers that have never purchased DLC before." While the expansion of the digital market is a good sign for the industry, we can't help wonder if GameStop's plan may eventually backfire. By introducing gamers to the idea of DLC, the company has taught consumers how to access and download content directly from the publishers themselves, via PlayStation Network and Xbox Live.