Who know that a vuvuzela could shoot poisonous darts from a great distance? No wonder they're talking about banning them, not just for their angry bee sound but they can be used as weapons.
De Rossi looks like a blow dart has hit him in the neck as he goes down. I don't think anyone knows how to dive better than the Italians, in terms of falling down beautifully. Watch De Rossi, there's an art to the dive. He does get clipped, stepped on, but makes it look like he's been shot.
1. De Rossi's left heel seems to have been stepped on by the trailing Uruguayan player. 2. De Rossi takes a stride before leaping off his right foot and then falling
Reference used - Morris, P.H & Lewis, D. 2008 Journal of Nonverbal Behavior, Tackling Diving: The Perception of Deceptive Intentions in Association Football (Soccer)
1. There was a slight separation in time between the contact on heel and De Rossi's reaction. 2. There is a lack of continuity between the heel contact and De Rossi's leap into the air. 3. There is contact consistency. De Rossi nurses his left foot where the likely contact occurred. 4. Upon leaping, De Rossi assumes the "Archer's Pose" tilting back his head, thrusting his chest forward, raising his arms and both legs bent at the knee to lift both feet off the ground to the rear. This is recognized as a characteristic sign of simulation, as the action is counter to normal reflex mechanisms to protect the body in a fall.
Conclusion: Although there was contact, De Rossi did indeed dive.
See De Rossi's dive at full speed in the video below.