I am contemplating taking the plunge with VoIP, particularly for when I am in Colorado but calling frequently to D.C. For that, I want a "202" area code, which is available from some providers but not others.
Just what VoIP does to the North American Numbering Plan, or NANP, will be interesting. The NANP is premised on geographical divisions of North America into different codes. Wireless eroded this premise somewhat. VoIP will continue that trend. What will be interesting to watch is if number shortages appear. One can imagine that "desirable" area codes like "202," "212," "312" will gain numbers, while other codes lose them. Of course, in a world of no long distance this doesn't matter for toll purposes. But, it can certainly have an effect for status and as a signaling device. For instance, if I am a securities broker, I might want a "212" to convey the impression that I am in New York. If I am a big shot think tank-er, I might want a "202" to convey that I am in Washington, instead of my back porch in Denver. [Secondary markets for cool area codes anyone?]
Area codes are a product of a specific time, a specific legal regime and a specific technology. A PhD thesis in 2020 will explain sociologically, legally and technologically how we dealt with the current paradigm shift that is going on.
And I didn't even mention SIP--the signaling system that will supplant the current numbering system, at least according to some.