The college student had endured months of online and cell-phone harassment from her ex-boyfriend. She ignored the barrage of eMails, changed her phone number, and dismantled online profiles to cut him off.
Then one evening, her cell phone signaled a new text message. It was him again.
"You should keep to yourself and stay away from other people," the message said, according to the student, who spoke on the condition of anonymity because she feared for her safety. Her ex had found her photo online and attached it.
As text messaging has boomed in recent years, it has also given rise to so-called...