SMS Autoresponder Interface for Cell Phones

It would be neat if there was a programmable interface whereby cell phones could automatically reply to SMS messages.

This might have practical applications --- a cell phone could give out information about its physical location in response to a properly-passworded query, to aid in figuring out where you left it or whether your kid is skipping school --- and expressive ones, the equivalent of custom auto-away messages in Instant Messenger programs: "I'm in class now, my phone is set to silent. I'll be checking messages at 2:30," or "Currently, I am listening to 'Swipe My Magstrip,' by Deloused." (The latter would of course be more useful in a world where people actually listen to music on their cell phones, but convergence is real and approaching.)

It's true that this might provide a vector for worms and other malware, in the same way that badly-written CGI scripts can compromise Web servers. But I wonder if the power isn't worth the risk.