To many who develop and use free software, the GNU General Public License represents an embodiment of the meaning of free software. In this paper we examine the definition and meaning of free software in the context of three events surrounding the GNU General Public License. We use a case involving the GPU software project to establish the importance of Freedom 0 in the meaning of free software. We analyze version 3 of the GNU General Public License and conclude that although a credible case can be made that the added restrictions are consistent with the definition of free software, the case requires subtle arguments. Strong arguments against the added restrictions are less subtle, and may therefore be more convincing to many users and developers. We also analyze the Affero General Public License and conclude that it is inconsistent with the definition of free software.