SMS is the ugly step-child of international communications, a thing that should cost $0, and should be easy has been made in to a nightmare to deploy and a patchwork of carrier related troubles.

I can fully understand their decision to go US only for now, but I really hope that at some point they'll be able to roll this out reliably world-wide, that alone would lay the world literally at their feet.

So many services are now hard to impossible to implement because there is no easy way of doing this, in my own site I would have several applications for it right away but only if I can guarantee international delivery.