A federal appeals court ruled yesterday that a World of Warcraft-playing bot violated the online game's terms of use, upholding a lower court's 2008 decision against the so-called Glider software, and issuing a permanent injunction against its use.

The Ninth Circuit U.S. Court of Appeals ruled (PDF file) that the MDY's Glider bot--which helps WoW players by automatically playing early levels of the massively popular game--is a breach of a contractual covenant. In a post on their Virtual World Law Blog, lawyers at the law firm Pillsbury Winthrop Shaw Pittman explained that the decision largely follows that of U.S. District Judge David Campbell, which enjoined the use of Glider in 2008.

But the Pillsbury Law firm--which represents ActivisionBlizzard in other matters, but isn't involved in this case--argued that the Ninth Circuit's conclusion that the Glider software was a breach of a contractual covenant means that Blizzard has different remedies available to it for breach of contract and copyright infringement than it did under the district court's original decision.

World of Warcraft is one of the most popular massively multiplayer online role-playing games in the world, with more than 11 million players. Last week, Blizzard released Cataclysm, the third major WoW expansion. In the first 24 hours of its release, Blizzard sold 3.3 million copies of Cataclysm.

The decision, Pillsbury's bloggers wrote, rested on the Ninth Circuit's determination that Glider circumvented Blizzard's Warden anti-bot detection program

According to Pillsbury, Glider did violate dynamic non-literal elements of WoW under the Digital Millennium Copyright Act (DMCA), but did not violate the DMCA "with respect to WoW's literal and individual non-literal elements."

"The Court also found that the tortious interference with contract claims were not preempted by the Copyright Act," the Pillsbury blog read, "but that factual issues prevented a proper summary judgment finding. As a result, it vacated the district court's summary judgment ruling on this issue and remanded the issue of personal liability for [Glider maker] MDY's CEO."

Prior to Blizzard's original lawsuit, MDY had sold 100,000 copies of the $25 bot software.