Dive summary:

• As more people switch from screen to screen, advertisers are searching for ways to reach them on every device; Undertone released today "ScreenShift" -- a responsive ad format that should help the industry overcome previous roadblocks. 
• Another advantage ScreenShift is boasting is measurement; the responsive ad format will be able to provide brands with per-screen based reporting. 
• ScreenShift was built using HTML 5 because Undertone was impressed with the results of Apple apps. 

From the article: 

"Undertone previewed ScreenShift with a L'Oreal spot. On desktops and tablets, the ad appears in a push-down format. On mobile devices, the ad overtakes the entire screen for 15 seconds (unless you close out earlier), and then it shrinks to a small ad unit at the top of the screen. The L'Oreal ad included an interactive swipe function on desktop and mobile devices."