The banner lets visitors play poker right on the page just having to give away their e-mail address.
At the end when the banner they promote a real poker site with sign up offers.
I see this is as another way of getting people to play where they want. Just imagine PokerStars, Full Tilt Poker and all the rest of the poker sites having a small version of their for fun client that you can put on your own site. It would be really cool.