You do know that American cellphone users send more text messages than they make calls on those phones, right? That was the case almost a year ago. "Since then, the average subscriber’s volume of text messages has shot upward by 64%, while the average number of calls has dropped slightly," the New York Times reports, citing Nielsen Mobile data. But forget about all that. It's the teen-texting data that really makes heads spin: 13-to-17-year-olds send or receive 1,742 messages a month. (It's downhill from there - 18-to-24-year-olds average a mere 790 a month.) The Times adds that "a separate study of teenagers with cellphones by Harris Interactive found that 42% of them claim that they can write text messages while blindfolded."