Microsoft is no stranger to antitrust litigation, with one example being the company's ongoing dispute with Datel Holdings. In 2009, the Xbox 360 peripheral maker filed suit against Microsoft after the publisher updated the Xbox 360's firmware to lock out "unauthorized memory units," such as the cheaper, higher-capacity ones offered by Datel.

The EFF is pro-Max Memory.

With that case continuing its slow trudge through the California court systems, Datel has found an ally in digital-rights advocate the Electronic Frontier Foundation. Specifically, in an amicus brief filed with the court, the EFF takes issue with Microsoft's claim that Xbox 360 owners who use a third-party memory card are violating the Digital Millennium Copyright Act.

"Letting Xbox owners use a third-party memory card does not put Microsoft at risk of copyright infringement," EFF Intellectual Property director Corynne McSherry said. "Microsoft is misusing the law in order to sell more accessories and control customers' use of the Xbox. The DMCA is supposed to be a shield against piracy, not a weapon to smash competition and consumer choice."

The EFF went on to note that, were Microsoft to win in its use of the DMCA in this instance, it would set a precedent allowing the company to prevent all competitors from selling Xbox 360-compatible devices, ranging from memory cards and controllers to headsets. This precedent could then also be applied to a range of other consumer products from other companies.

Datel's original suit accused Microsoft of violating antitrust laws by requiring Xbox 360 owners to buy only Microsoft-made accessories. It asserts that doing so is an illegal practice, tantamount to a car manufacturer forcing auto owners to buy only a certain brand of tires in perpetuity.

Microsoft had not responded to GameSpot's request for comment as of press time. The EFF's amicus brief can be viewed in full through the organization's website.