I think you will appreciate, as I did, these fundamentals for working with young cellphone users on the best ways and places to use those phones. They're from author and parenting specialist Jan Faull. She looks at where to talk, when to talk, and the example we grownup cellphone users are setting for them. Here are a couple more pointers I would add: 1) Know when and how much your child is using his mobile – for talking and texting (the latter being silent, so harder to get a handle on) – and establish boundaries. 2) Know what else she's using her phone for (photo-sharing? video-uploading?) and talk about the implications for her and other people in what's being shared. See also ConnectSafely.org's "Cellphone Safety Tips" and this on a study about the role of cellphones in "teen dating abuse" and what parents know about it.