It looks as Ronaldo is dragging his leg to make contact. There should be some action for him for simulation.
I'm all for banning divers, everyone is giving the ref a hammering after this balls up which is fair because it was blatently not a peno. But the problem is its to easy for players like Ronaldo to go looking for penalties, he would have gone to ground regardless of whether there was contact or not in that tackle.
A yellow for diving is no way near enough for something which ruins the game, we need to deter players from playing for peno's. I know they hand out bans in Italy as someone got a 2 game ban a while back after winning a peno with a blatent dive. Does our FA take any action against divers yet? I haven't seen any.
Though to be fair in this situation you couldn't punish ronaldo, it was blatently a fair challenge but there is slight contact, so even though everyone knows it wasn't enough to trip him punishment in such cases would cause dispute as to was it actually a dive, or did he just go down because the contact was enough to knock him over - Its opinion and in some cases very hard to judge.
The only way the rule could be used is in cases where there is no doubt the player has gone to ground for no other reason than to try and cheat the ref - no contact instances. Then it should be at least the same punishment as a red card, with increasing bans for repeat offenders.
This would at least deter players from pre-empting dives and maybe lessen the need for video footage - though I think this should be utilised for goal line decisions.