Here's a potential lead: According to Crain's 2008 Book of Lists, Chicagoans of "mixed race" use their cell phones more than any other demographic group (putting in 1,469 minutes per month), followed by blacks (1,365), Asian/Pacific Islanders (1,171) and whites (638). Local Native Americans use their cell phones least, at 243 minutes (oh, and thank Telephia for the stats). Anyone have any theories? Well, come back with some research results for us in 2010 or thereabouts, m'kay?