The GNU Affero General Public License (GNU AGPL) is a free, copyleft license published by the Free Software Foundation in November 2007, and based on the GNU General Public License, version 3 and the Affero General Public License.
The Free Software Foundation has recommended that the GNU AGPLv3 be considered for any software that will commonly be run over a network. The Free Software Foundation explains the need for the license in the case when a free program is run on a server:
The GNU Affero General Public License is a modified version of the ordinary GNU GPL version 3. It has one added requirement: if you run a modified program on a server and let other users communicate with it there, your server must also allow them to download the source code corresponding to the modified version running there.
The purpose of the GNU Affero GPL is to prevent a problem that affects developers of free programs that are often used on servers.
The Open Source Initiative approved the GNU AGPLv3 as an open source license in March 2008 after the company Funambol submitted it for consideration through its CEO Fabrizio Capobianco...