The expulsion of Austin Carroll, 17, from school after he tweeted the F-word multiple times one night while fighting insomnia, is stirring a debate over how closely school officials can monitor students' non-school online activities. (Pam Smith via Associated Press)

The expulsion of Austin Carroll, 17, from school after he tweeted the F-word multiple times one night while fighting insomnia, is stirring a debate over how closely school officials can monitor students' non-school online activities. (Pam Smith via Associated Press)