Asterisk makes it very simple to publish your SIP URI.

ENUM is fully supported so it is very simple to translate your old e.164 address to your sip URI. Several free ENUM services are emerging.

It’s a drop in the bucket not only from a percentage a traffic basis and even when compared to proprietary Voip solutions, every day a bit more traction is obtained.

Every Asterisk system I setup has a sip alias for each extension. With two ENUM enabled SIP servers your dream of complete circuit switched bypass is realized. From the users perspective they dialed a regular phone number.

All revolutions start with a whisper.

With VoIP like Vonage (and all Vonage clones), all that is exposed to the end-user is an analog POTS wire, just like the old phone company exposed. with Skype, all that is exposed is a closed proprietary client (not a protocol). That leads us nowhere.

Why I like Email as an analogy over Web for SIP is that Web is strictly a client/server solitary affair, whereas email crosses domains and connects end-points in a more client-server-client fashion, which is much closer to how VoIP with SIP works.

If we take email or the web as the analogy, probably more people have their email or web site hosted somewhere (by a service provider), but there’s nothing stopping them from hosting it themselves as many also do. That’s because the protocols are known and exposed to the end-users and at the server provider borders. If the VoIP providers exposed the protocol across domains (at their borders), then the same thing could occur with VoIP – but really, whether someone runs their own server or not is orthogonal to the problem.