If I go to http://mm-ch.wmflabs.org/wiki/Special:CreateMassMessageList and type in "Privacy policy" as the title, there's no warning until after I submit the form that this page title is already in use.
We can use AJAX to inform the user that the title is already taken before form submission.
Version: unspecified
Severity: enhancement
Whiteboard: gci2014
URL: http://mm-ch.wmflabs.org/wiki/Special:CreateMassMessageList