Gartner adds that for many developers the outlay for ads is close to the maximum ad income or even exceeds it.

FORBES: Worldwide Mobile Ad Revs To Grow 19% In 2013, Gartner Says

Executives at Google have said they are devoting resources to close gaps in the ad rates they make from mobile devices compared with PCs.

WSJ: Twitter's Mobile Ads Begin to Click

Now close your eyes and try to tell me about a display ad you saw lately.

FORBES: Online Display Ads: The Brand Awareness Black Hole

The carriers want to generate revenue, and those close to the negotiations say they have been pressing Google about the duration of ad-sharing, the percentage cut they would receive and in what form.

FORBES: Magazine Article