Want to know who your friends are? Ask your cellphone - http://www.newscientist.com/article/dn17624-want-to-know-who-your-friends-ar... You might think you are the world authority on your network of friends and acquaintances. But the cellphone in your pocket may be better at tracking your relationships than you are. That's a finding of a study which opens new possibilities for social scientists, epidemiologists and other researchers who want to know how people connect and interact socially.