Variation on "in his cups" (i.e. inebriated): someone so concentrated/"zoned" on whatever message(s) coming forth from his/her BlackBerry/iPhone/Android device that literally everything else surrounding them (non-virtually-speaking) is reduced to literal background noise. Commonly encountered on the street, on public transport, or even in a bar.
Bill: Hey, Roger...Roger? Earth to Roger?
George: Never mind Rog, he's in his BlackBerry again.