Interestingly the main "carriers' showing up for mobile for me are (Time Warner) Roadrunner and Comcast, which implies a lot of mobile usage is tethered to wi-fi at home. iPhone, iPod and iPad dominate, but Android is catching up.
I have a netbook computer I purchased from Verizon. I can connect to the Internet via Verizon's wireless service (built-in antennae, not an air card) or via WiFi when a service is available where I am at the time.
I wonder how my visits would be reported to a webmaster - mobile visitor?