I use my phone a lot during the day, but that's because I'm not sure if I would categorize it first and foremost as a book reader or communications device. I spend much lot more time reading books/fiction on it than I do using it as a communication device (and don't use any social networks beyond HN), but the communication aspects of it are so important that I can't easily discount them as secondary.

Interestingly, if I carried a paperback around with me, and pulled it out to read it when waiting for things, and read it before bed, would I be considered to have a "page time" problem, or is that more acceptable? If it's more acceptable, maybe that points to this being less a problem about spending time on the phone, and more about what we spend our time on in general.