Stickster writes "Back in 2007, IP Innovation filed a lawsuit against Red Hat and Novell. IP Innovation is a subsidiary of Acacia Technologies. You may have heard of them — they're reported to be the most litigious patent troll in the USA, meaning they produce nothing of value other than money from those whom they sue (or threaten to sue) over patent issues. They're alleging infringement of patents on a user interface that has multiple workspaces. Hard to say just what they mean (which is often a problem in software patents), but it sounds a lot like functionality that pretty much all programmers and consumers use. That patent was filed back on March 25, 1987 by some folks at Xerox/PARC, which means that prior art dated before then is helpful — and art dated before March 25, 1986 is the most useful. (That means art found in a Linux distribution may not help, seeing as how Linus Torvalds first began the Linux kernel in 1991.) Red Hat has invited the community to join in the fight against the patent trolls by identifying prior art. They are coordinating efforts through the Post Issue Peer to Patent site, which is administered by the Center for Patent Innovations at the New York Law School, in conjunction with the US Patent and Trademark Office."