Well, 6 of my friends have now tried to join the multiplayer game example. No one has been able to connect..
So i guess multiplayer is not really working for public players..
EDIT:
One of my friends was finally able to connect with someone named clayto (maybe from scirra)
But we were never able to connect again or join anything after that..
what a shame - i was looking forward to adding multiplayer features to my game. Oh well another idea dead as usual by the limitations ..