Marketers can't remember this often enough: Mobile is not one screen or two screens. Or three screens (smartphone, tablet, and e-reader). Or four (ultrabook). Or five (phablet). Or six (fill in the blank with whatever connected device consumers will be flocking to next.) Google Glass? The Apple iWatch? Mobile is a behavior. The only common thread uniting the vast and diverse mobile arena is that consumers are taking a connected device with them on the go.