That's the MAIN reason... however there are other smaller differences as well. Smartphones usually lean more toward the phone-side of the combination of a hand held computer and a phone, where PPC lean closer to the hand held computer side. Smartphones typicaly carry a more reduced version of an OS (e.g.: Smartphone = WM 6.1 Standard, PPC = WM 6.1 Pro). It's a darn shame that AT&T groups smartphones with QWERTY keyboards in the same group as PPC's. I really think they could help define the market between the two. Alot of times people would prefer the ease of a smartphone, but end of getting sold on the PPC by a salesmen.