It's enormous.
There is a lot of money in social games, but without getting a lot more users (hard when CityVille is hitting 100 million+) or getting much better conversion rates, Zynga is unlikely to see revenue from social games that matches their current value.
Our studio (Treyarch) was acquired for around 5-15mln (not sure the right number), close number for Infinity Ward and other studios (there is report on the net about public numbers).
But $750mln? Isn't the Pandemic acquisition pandemic enough? Who the fuck drives EA?
Btw, singly.com looks awesome, and telehash seems very interesting!