These are being implemented as CFD (contract for difference) futures.  As far as I can understand, they do not represent any actual holding of Bitcoin, the exchanges do not possess any "reserve" of Bitcoin, and there is no option (at this time) to "take delivery" of a settled contract in Bitcoin.  So it's basically betting on the price of Bitcoin at each contract's strike date.

I am more interested in how people in the community feel that a futures contract that is wholly disconnected from the underlying asset (BTC) will impact the price of BTC.  I posted a similar thread about that particular aspect.

I guess we'll know starting next week, but it's looking more to me as a way that they can sell clients on "paper Bitcoin" than something that could actually manipulate the real BTC price.  At least for now while they're totally disconnected from actual BTC.