Why can't Zynga use their games as a means to move its users outside of the FB wall and into a Zynga-only platform? It seems that many of Zynga's users would do almost anything for some free game credits.

Zynga can (and will ) I just think it adds a more difficulty to retaining customers, and getting the free advertising on facebook through messages and requests etc. as people log-in zlive and don't play on fb.

But here's the worst from Zynga's side:

I dont think there is anyway Zynga can move people over fast enough -- fb will own a large chunk of user data (and realistically that's the big advantage Zynga has right now -- copying gameplay is easy, analytic packages are out there like mixpanel to optimize ROI on ads).

This really signals fb must really see gaming as a pathway to significant profits, and fb is will own the data on the most active and profitable players ( time spent, new games tried and with fb currency $ spent etc.) and could always expose this data to advertisers in some fashion to commaditize the market further.