Why does AT&T charge $110 for its "GigaPower" Ethernet service in Chicago and only $70 in San Antonio? The company won't say, but I have a pretty good idea: competition.

Cities in which Google offers its $70-a-month high speed Internet service enjoy AT&T's rival offering for about the same price. However, in cities where AT&T is the only option, or at least the only large provider, the company charges more.