How do ISPs work? [bandwidth bill = electricity bill]

[Lebombo]

Actually, that leads to a question of which ISPs do public libraries use? They are part of the government, so the question might became, what ISP does the government use?
EDIT: I apologize for calling ATT's business plan crony capitalism. Its just capitalism, crony doesn't fit in this context because ATT seems to be pushing ahead based on merit, not anything that could be considered dubious. However, I'm sure there will be some favoritism at play when ISPs begin to make exclusive deals with some web content providers over others.