AT&T and BellSouth, among other companies, have suggested that they would charge popular sites like Google and Yahoo! for especially reliable delivery of their content as a means of recuperating some of their investment into upgrading the Internet's backbone.

The United States Telecom Association has said the Internet is dependent upon continued investment into its networks.

Opponents of the plan say the communications companies are already earning money from those networks by charging Internet users for their access.

Google's complaint suggested that charging a premium for more reliable delivery could limit the variety of material available on the Web.

Last week, Google sparked discussion by banning Web sites for Ricoh from its search results.