"Isn't that after all the goal of advertising? To cause a transaction. So why not do away with the intermediate step of sending someone to a website for more information? Especially with the limited screen real estate on the phone, there isn't really room for the contextual text advertising that made Google its billions. Interstitial or popup ads are intrusive and unwelcome. But how much search activity on the phone is tied to commerce already? Find a restaurant nearby and make a reservation? Why not pay as well?" - ivanandersson