> 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.
AGPL is GPL3 but better IMO.