GNU Affero General Public License

The GNU Affero General Public License is a copyleft license for software that is intended to be run on web servers like web applications. Like the GNU General Public License, the Affero license allows you to use, copy and change the code of software, but requires that you release your changes if you distribute the software or you run a modified copy on a web server on the Internet.
The Affero license is intended to make it harder for people to avoid releasing modifications to free software by running the software as a Web service (see software as a service).