The Milken Institute Review has an article by Robert W. Crandall, Robert W. Hahn, Robert E. Litan and Scott Wallsten, who note that
Jerry Hausman of MIT has estimated that taxes on interstate and international telephone revenues that are used to support low-income subscribers, high-cost carriers, schools, libraries and rural health facilities, are about three times more costly to the economy than the same sums would be if they were raised through general income or consumption taxes.
The article is about Internet telephony, which the authors say undermines the rationale for regulating local phone service, because it takes away the dominance of the Baby Bells.
Meanwhile, Kevin Werbach argues that voice over Internet Protocol is more than just telephony. For example,
Microsoft, with its XBox live online gaming service...has over one million paying customers for multi-player online games. And all of them have a headset that plugs into the game console, enabling real-time voice communications with other players.