Mobile advertising is taking off around the world, fueled by the growth of smartphone adoption and more affordable data plans. Ad spending nearly doubled last year, and it will continue the big gains this year, though there are some major shifts coming to the medium. Global mobile advertising revenue increased by 92 percent last year, to $19.3 billion, according to a new report from the Interactive Advertising Bureau’s Mobile Marketing Center of Excellence, IAB Europe and IHS Technology. That’s up from just over $10 billion in 2012.