I have written previously about my personal favorite new voice application - voice messaging. Ztel now has a service they call the Personal Voice Assistant (PVA). I strongly encourage anyone interested in this space to review the demo to get a sense for the direction the VoIP value-add service market will take. And to think that the markets believe that voice is a mature segment ;)Ruminations on Telecom and the Economy: Ch-ch-ch-ch-Changes
I've also recently found out about CallTrex, which seems to be heading in the same direction: offer can't-get-elsewhere voice features that people are willing to pay money for.
With base prices of VoIP plummeting and only International long distance having any kind of profit (or, for that matter, charge!) associated, providers will need to add more features to stay profitable.
Think about it: all the basic features that telcos have been charging $4 - $5 - $8 per month for are often bundled into a VoIP service for free. And that doesn't even take into account advanced features you can't get from your local telco, like 5-way calling or voicemail via email.
Oh boy is it going to be fun watching this train wreck.