Time Warner recently announced that the company intends to consider a usage-based system. This means that users (cable customers) would pay depending on how much bandwidth they use. If they go over the allotted bandwidth on their plan, they get charged overage fees. The system works much like cell phone minutes with customers having the choice of four plans at five, ten, 20 and 40 gigabytes.
The story discusses the impact this could have on XBL, gaming, and movie downloads. But this could apply to all the internet capable gaming consoles and PCs.