Thanks the deity of your choice for this one. Since I have moved into my current building, I've been in 2 separate offices that attracted cell phone users; one because it was outside of a training room and now because I am near an exit by bunch of cubes where people can't have a private conversation. What I've noticed since I've been here is:
1) People on cell phones talk much louder than people speaking or even people on regular phones
2) Because people tend to be making personal calls, there's more silly giggling and more "dude"s or "honey"s and recaps of social excursions. Much more distracting than business conversation.
3) Some people think that holding that electronic device up to their ear makes them invisible.
4) It also gives them a blind spot around anyone else within earshot, even if that person rudely pushes their door closed with their foot ; )
Seriously, cannot imagine one of these people sitting next to me on a plane! There's not enough wine in Italy to make me OK with that.