Worlds Incorporated has filed a patent infringement lawsuit against Microsoft over the technology in Minecraft. The company describes itself as "a leading intellectual property developer and licensee of patents related to 3D online virtual worlds," which would make lawsuits one of the primary products they manufacture. They say Minecraft infringes on U.S. Patent No. 8,082,501, titled "System and Method for Enabling Users to Interact in a Virtual Space," which they call the "’501 Patent" for short. Word is this is not their first rodeo in going after game companies with this IP. Here's the 411 on 501 and the legal action:

The ’501 Patent was previously asserted against Activision Blizzard, Inc., though that litigation was temporarily suspended after the patent’s validity was challenged in 2015 in an inter partes review petition filed by Bungie, Inc. with the U.S. Patent & Trademark Office’s Patent Trial and Appeal Board (PTAB). The defense of the ’501 Patent included a trip to the U.S. Court of Appeals for the Federal Court (CAFC), where Worlds’ legal team, led by Wayne M. Helge of Davidson, Berquist, Jackson & Gowdey, LLP (DBJG), convinced the CAFC that the PTAB had applied an incorrect test as part of its analysis. Finally, on January 14, 2020, the ’501 Patent emerged from the inter partes review process with all claims intact.

“Our expert legal team at DBJG defended the ’501 Patent before the PTAB, and convinced the CAFC to reverse and remand unfavorable PTAB decisions against Worlds’ patents," stated Thom Kidrin, Worlds Inc. CEO. “The CAFC’s ruling instructed the PTAB to reconsider the methods it used to evaluate the relationship between Activision and Bungie, and provided strong guidance on the rules to follow on remand. In January of this year, the PTAB dismissed all of Bungie’s challenges against the ’501 Patent. Then in April, Worlds successfully convinced the U.S. District Court in Massachusetts to lift the stay on Worlds’ active litigation against Activision, and that case is now proceeding toward trial. Meanwhile, Worlds asserted another of its patents against Linden Lab’s “Second Life” product. Bringing this latest case against Microsoft is the next step in our ongoing process of enforcing Worlds’ intellectual property rights against companies that have been using our proprietary technology.”