nomis5 - 6:04 am on Sep 26, 2012 (gmt 0)
I have a mobile version of a couple of sites. It's interesting because the content on the desktop sites is the same as on the mobile sites.
The CTR for the mobile site is about 175% of the desktop site for this month. RPM is a tiny bit higher for the mobile site. And I'm comparing the same ad size of both mobile and desktop sites.
That indicates to me that "large thumbs" are not the reason for the high CTR on pages viewed via mobiles. It would appear that the CTR is naturally higher for mobile users.