You have to think about how this works. The confusing word in all of these systems is "calls". Do not confuse the calls with that of the landline (POTS) or cellular systems. All phone systems are point-to-point, what varies between them is how you get from "point-to-point". What these Internet systems do is give you a computer application that digitizes your voice and sends it to another user whose app plays your voice out the speaker. The reverse occurs with the response message. It is really that simple. The complexity comes with getting full-duplex behavior, real-time audio, etc.--but those are just details in the big scheme of things.

The other issue is the link-up between you and who you are trying to call. A landline phone system uses complex routing networks and electronic switches to hook your phone up to who you are trying to call. Obviously, you cannot call your aunt in backwater Louisiana if she doesn't have a phone. What makes you think you could call someone that was not on the Internet?

Opps...I forgot. The company doing the Internet phone system could allow connection into the global POTS; i.e., you make a call via Internet on your computer then they route your call into the POTS. Wait a minute, whose paying for the call--you can bet they won't.

The other confusion is in end-user equipment. The POTS and cellular systems use standard hardware. My V3c that I use on Verizon has the same "telephone" interface as the Razr that someone on Cingular has. The only difference is features and security protocols. Likewise, you can go to a dollar store and pick up a phone that will plug into any POTS jack in the world and work, providing you have "service". This does not exist in the Internet phone biz--but Google and Nokia are trying hard.