Specifically, while iOS was the leading mobile platform, Android was the leader for mobile phones with 30.94% of mobile impressions for the whole year, edging out the 29.08% of impressions that were sent over the iPhone. But when it came to monetizing the ads, the iPhone had over 37.28% of revenue while Android had 29.97%. The Samsung Galaxy S III alone, accounts for 9% of the Android ad market.
Opera also pointed out in its report that new features found on today's smartphones allow for rich media campaigns that are high impact. DreamWorks Animation and Kraft Foods were two examples of companies using new branded content and embedded calls to action as ways to engage the interest of smartphone users. You can see the examples of those campaigns in the slideshow below.
source: Opera via Slashgear