Google has just announced improvements in mobile search advertising. (See the Google Blog post for more information.) Apps that incorporate search capabilities will see more relevant ads appearing on their screens.
To date, mobile ads appearing on smartphones have not been particularly relevant to the nature of the apps displaying them. In contrast, desktop search ads are highly relevant to the search terms used. So, for example, if I'm searching for information on bicycles, I'll see ads related to this topic.
Making mobile ads more targeted should improve ad click through rates and improve user satisfaction.
If I'm searching on my smartphone for bicycles, I'll see ads related to bicycles, including information on bicycle shops near my current location.