This is what the Affero GPL was designed to combat: From the AGPL preamble: (http://www.gnu.org/licenses/agpl-3.0.html http://www.gnu.org/licenses/agpl-3.0.htm

This is what the Affero GPL was designed to combat: From the AGPL preamble: (http://www.gnu.org/licenses/agpl-3.0.html http://www.gnu.org/licenses/agpl-3.0.html) ... The GNU General Public License permits making a modified version and letting the public access it on a server without ever releasing its source code to the public. The GNU Affero General Public License is designed specifically to ensure that, in such cases, the modified source code becomes available to the community. It requires the operator of a network server to provide the source code of the modified version running there to the users of that server. Therefore, public use of a modified version, on a publicly accessible server, gives the public access to the source code of the modified version.