Virtual Goods
Inside Virtual Goods: U.S. virtual goods market to hit $2.1 billion in 2011; http://j.mp/b0YtUe
Dumenco: How (and why) Facebook and Twitter became recess for grown-ups; http://j.mp/cdCYnU
Zynga, Playfish, Playdom: generating as much as US$ 300 million annually on sales of virtual goods; http://j.mp/2jZyGy