So, you do something in a virtual world and you get a random item. Say, you kill a dragon. The item has real-world value. You obtained it as a result of three things: You paid or registered to play the game, you performed an action that may have required skill or maybe not, and the system executed a random item generation process. Still, it's not gambling. Right? It's monster-raiding.
OK, now you go into a social network and do something and you get a random virtual item of nontrivial value. Say, you 'Liked' somebody's pic and you got a free virtual rose. Or you wrote something that 100 other people 'Liked.' But you joined the network, you did something that may or may not have involved skill, and a random process of the system gave you an item of value.
We need to be firm at some point that there's a difference between killing monsters in games and 'Liking' things in social networks. It's not a technical or functional difference, its an aesthetic and experiential difference for which there is no bright line distinction. If we don't work to clarify this difference, courts will start calling monster loot gambling income. Not good.
Game worlds need to be identified as such and then tightly walled off, to the extent possible, from reality.