Could Google Fibre have some sort of inbuilt P2P, a bit like SpaceMonkeh? (In the modem/router.)
So, a Google owned encrypted p2p cloud storage network that is maintained in their customers homes. They could allocate a % of customers speed to the upkeep of this.
I think it is a given that they will stipulate that all their customers have a shared WiFi. A bit like BT's BTFON, but one you cannot turn off. I guess this will help with Google Glass connections when roaming.
Would you even consider Google as an ISP?
Maybe they will just install a BitCoin miner on all their routers so we basically pay the energy costs for their global mining operation haha