Very very good points. Facebook interacts with the real world and that's why it's disruptive.

Social Games also interact with the real world.

This is confusing.

This is a really good point. And one that's been made about games time and time again.

Mario was super-successful because of its game verb. It is a game about jumping. And that's all it does and it does it very well.

Most RPGs have loads of game mechanics but they're primarily about the story. And that's all they do.

You do get jumping and shooting games. But there's a gestalt thing going on there.