lots of things don't have an explicit result message - they either work silently, or die horribly. Having a flash message thing could be an improvement.
Personally, I'd implement this by doing set_cookie("shm_flash", "message goes here") on the server side, then layout.class.php can add some code to grab it, insert the message into the page, and delete the cookie.
flash_message(str) added in master; now to use it in all the places that make sense... (other people reading this, please comment with suggestions /o/)
Actually, a little improvement would be useful: set a type (success / info / error)