It used to be said of some people that they "watched a lot of television". In those days there was nothing else to watch, in that kind of way.
But how do I describe what is being done today ?
Are people "watching a lot of phone" ? Are they "doing a lot of phone" ? Are they "interacting a lot, on phone" ?
If I say "they are doing a lot of phoning" that would imply they are actually on the telephone, rather than tweeting/facebooking/instagramming/texting.
How else do I describe what they are doing ?