I suppose like PC gaming, you'll have the EAs, 2Ks, Activisions whom own many other companies in a way to control the products.
I don't know about Facebooks revenue, but I just did a little search on Farmville which is a popular Facebook game and happens to have been created by a pretty well known name in these parts, Mr Brain Reynolds (dammit Brian where's my Rise of Nations 2!) and here's a guess on income:
http://latimesblogs.latimes.com/ent...-games-make-money-lessons-from-farmville.html
"To start with, Reynolds threw out some bare bones data:
* Social games cost between $100,000 to $300,000 to make.
* Between 3% and 5% of people who play social games pay money for virtual goods in the game or sign up for advertising "offers" that generate cash for the developer.
* Farmville is played by about 31 million people every day.
Now let's suppose that, given these ballpark figures, that each person who plays a social game generates, on average, a penny a day. Multiply that penny by the number of days in a year, 365, and you get an average of $3.65 generated per year per person.
If you are Farmville, you multiply that by the number of people who play your game on a daily basis:
* $3.65 x 31 million people = $113 million a year"