Is there a detailed and up to date tutorial for this problem? I found one that uses a private MySQL server and PHP script, but also Webstorage, which has been phased out. Facebook object is pretty limited in its capabilities.
In fact, a Scirra-run MySQL server would be nice added value for paid licence users, along with some help on Javascript fo sharing screenshots, inviting friends, posting to friends' walls etc. This is quite crucial nowadays for viral marketing.