Regardless of what you may think about Zynga, the numbers reported to be playing FarmVille are astonishing. This is due, in no small part, to the viral manner in which the game is distributed via Facebook.
I spent the morning having a quick look at the Facebook API when it suddenly dawned on me - Silverlight Applications (and therefore games) are supported. A few hours later I'd been able to set up a quick test App using the latest Awakener build:
Note: The App itself has not been submitted to the Facebook Application Directory and it is linking to the game via a local host, but it's pleasing how simple this proof-of-concept has been.
There's a lot of potential with this. It could be used as a means of distributing a demo and raising awareness for a commercial game, or it could be used to give freeware games a larger audience (with, perhaps, a paypal donate button attached to the app). Or there could be integration with Facebook Credits e.g. reach a certain level and you need to cough up to keep playing, similar to the Xbox Indie Trial system.
Chances are I'll need a new 'Publish to Facebook' option in XAGE Editor.