Zynga Inc (ZNGA)

[xlt leader]

http://www.infiniteedgegaming.com/business-development/playing-around-with-zynga-poker-numbers/

The largest listed online real money online provider is Partygaming. They earn roughly $15,000,000 per month in rake revenues. To match that, Zynga Poker has to squeeze, on average, fourty cents out of each session. That’s equal to engaging in a couple of hands of 0.25/0.5 NL depending on how rake is distributed.
The cheapest official Zynga chips purchase I could find was $2.30 for $150,000 chips. So if every fifth Zynga session leads to a player going “broke” and reloading, I’m easily matching Partygaming in revenues.

This doesn't take into account advertising revenues. With on-line gaming in the US becoming a reality there will be a tidal wave of revenue opportunities for Zynga