Growing number of educators feel it's crucial for making kids digitally literate. The principal of New Milford (N.J.) High School has nearly 12,300 Twitter followers (his handle: @NMHS_Principal). He and his teachers use Facebook to communicate with students and parents, and students use it to plan events. In class, teachers routinely ask kids to power up their cellphones to respond to classroom polls and quizzes. Rather than ban cellphones, Sheninger calls them "mobile learning devices."