The widespread availability of unlimited text messaging cell phone plans has led to a shift in the way US teens communicate. For the first time, most teens are more likely to text one another than call each other on the phone. A recent study found that more than 30 percent of American teens send at least 100 texts a day, while 15 percent send more than 200. Girls tend to text more than boys, typically sending and receiving 80 messages per day compared to 30 for boys.