Google's move to snap up mobile-advertising startup AdMob is a leading indicator that your smartphone is about to overtake your laptop as the instrument of choice.

Fortune's Jon Fortt has a smart piece, "The Race to Own the Mobile Internet (at least the annoying ads)," which notes the Street's strong approval of Google's pending $750 million purchase of the company that specializes in teeny-tiny display ads. (Click above for AdMob's ad campaign touting its ad campaigns.)

Fortt's skeptical that display ads will work all that well on the small screen — and right now, he notes, the annual money spent on mobile advertising is only $416 million, compared with nearly $24 billion spent on online advertising. But Google is Google, so bet against the giant Android at your peril. And get ready for a blizzard of display ads on your fancy little smartphone.