diff --git a/docs/sources/reference/commandline/cli.rst b/docs/sources/reference/commandline/cli.rst
index a0b2115987..a9fc9100a0 100644
--- a/docs/sources/reference/commandline/cli.rst
+++ b/docs/sources/reference/commandline/cli.rst
@@ -63,7 +63,10 @@ the ``-H`` flag for the client.
         # both are equal
 
 
-To run the daemon with socket activation, use ``docker -d -H fd://*``. Individual sockets can also be specified ``docker -d -H fd://3``.
+To run the daemon with `socket activation <http://0pointer.de/blog/projects/socket-activation.html>`, use ``docker -d -H fd://*``.
+Using ``fd://*`` will work perfectly for most setups but you can also specify individual sockets too ``docker -d -H fd://3``.
+If the specified socket activated files aren't found then docker will exit.
+You can find examples of using socket activation with docker and systemd in the `docker source tree <https://github.com/dotcloud/docker/blob/master/contrib/init/systemd/socket-activation/>`.
 
 .. _cli_attach: