The idea is very simple.
While we look at a photo or video, we will prefer to use every inch of the small screen (3-5 inch).
But, when reading text or text ad, our eye focuses at the centre of the screen, merely about 1 inch.
If we search Google or Bing, the small screen will display 3 results. After the eye focus moves from the first result to the second one we are not interested any more with the first result. The area of this first result, which we just abandoned, will be the new "real estate".
In this area, we can smooth a text ad (from right to left) with the same up and down finger smooth of the user.
This ad will disappear at the top of the screen with the up finger movement of the user.
immediately After the first the 1st ad a 2nd ad will start to smooth
contact us: firstname.lastname@example.org