I'm glad I attended the inaugural twilio conference. It was great to see so many Web developers show up with enthusiasm for Voice & SMS in what is otherwise a time dominated by developer interest in mobile Apps instead of services. I spoke with a few developers who I hadn't met previously, and it was clear the enthusiasm and interest stems from two principles:

Simplicity - the twilio API is brain-dead simple to use
Ubiquity - Voice & SMS are lowest common denominator technologies that work everywhere and on every device

Complexity kills. Simplicity always wins.

I was also asked about my thoughts on over-the-top voice and SMS by way of twilio client. My answer was I think it's wonderful for next generation data networks! The more data pushed through the network, the better!