There is some fascinating data in a new comScore release comparing reach for various popular web services across PC and mobile platforms. Weather, sport, and email draw disproportionately on mobile ([as would realtime parking data, if it were available there, darn it], and search is a surprising laggard.
The puzzle, of course, is why search does so poorly. Aren't people looking for things when they're out of the house? Is it a function of crummy browsers on mobiles? Is it a not-on-the-phone-deck issue? I'm guessing it's a little of all of the above, and that we will see big changes in these reach ratios over the next few years, with search rising, email staying stable, and other services -- like parking! -- coming to the fore.