We have talked about the end-to-end principle of network design and the idea that routers treat all packets the same. Now that a few telephone and cable companies control much of the ISP business in the US, they are seeking legislation that will allow them to program IP routers to examine packets. This would allow them to bill for specific services and give delivery priority to their content or that of those who pay a premium. Here is Vint Cerf's advice to congress on this bill. You can also listen to a brief roundtable discussion of this effort.