The Free Software Foundation (FSF) has just memorialized the Affero GPLv3, a version of the GPL that was created to cover software that runs over a network such as the Internet, which these days would mean, oh, SaaS stuff and Google Apps, Web Services, game servers, web and e-mail servers, that kinda stuff. It's based on the GPLv3 but adds a codicil that lets users who interact with AGPLv3-licensed software over a network get the source code to that program. It's meant to force more software modifications to be shared by removing the protection of the server. The Affero license started outside the Free Software Foundation - the operation behind the GPL - but it concert with it because the GPL hadn't anticipated protecting works accessed over the Internet. The FSF now maintains the Affero license and published two drafts of AGPLv3 this summer seeking feedback.