When You Search on Your Phone, You Click on More Ads. On Purpose?

More phones and more tablets means more advertisers are spending more money on mobile search. Last fall, Google said it was on pace to generate $2.5 billion from mobile ads, and search marketer Marin Software figures that by the end of this year, nearly 25 percent of Google’s U.S. search ad dollars will be spent on mobile. But the mobile Web is still so new — remember, the iPhone is less than five years old, and the iPad is just two years old — that marketers are still trying to figure out how people use it when they search, and what that means for search ads.