Morty writes "So, why hasn't the GPL been successfully challenged yet? In this article, Eben Moglen, General Counsel to the FSF, explains that the GPL is in a stronger legal position than most licenses. Most licenses restrict the user from doing what would otherwise be legal. Because the GPL (and presumably, other free/open software licenses) let the user do things that are otherwise illegal (copy and redistribute software), the GPL is in a stronger position to dictate terms. If the user doesn't accept the terms of the GPL, the default is for copying and redistribution to be forbidden under copyright law. I had never looked at it that way before. . ."