My bank sends me a text alert when my account balance is low. My wireless company sends me a text alert when I'm about to use up my monthly data. Somebody — I guess the National Oceanic and Atmospheric Administration? --sends me a text alert when it's going to rain a whole lot.
A few clever researchers said: "Hey! What if we could send text alerts to parents when students miss class or don't turn in their homework?" And what do you know, it worked.