And college students who are pressed for time, like Ben Blanton, a freshman who plays baseball at Vanderbilt University in Tennessee, can text their parents when it suits them.

• 而时间经常不够用的大学生，像是在田纳西州范德堡大学打棒球校队的大一新生班?布蓝顿，也可以在双方都方便的时候传手机简讯给父母。