Until now, you were able to promote your application only if it belonged to you and only if you had previously registered and configured it on Facebook.
Now everyone has the "Application" tab visible, and the app is promotable just inserting, at Step 2, a valid URL redirecting to an app Store!
Reminder: the Application, even if it's not yours, MUST have been previously registered on Facebook, otherwise you'll receive a validation error! Need to register your app? You can do so here.