Interoperability is a fairly necessary component to communications, and it’s not a trivial issue. InPhonic has made a go of it, and is growing at breakneck speeds. And, as VeriSign and NeuStar (and InPhonic) both handle core components of this interoperability, communications networks become increasingly complex, service providers are melding together across mediums (utp, gsm, cable, dsl, wifi, etc) to handle VoIP, MVNO’s are percolating from all walks of life, and as there are increasingly more companies playing ball, the party is only going to get much BIGGER.