Google launched a new mobile ad unit for AdSense named "mobile anchor ads."
Mobile anchor ads let users swipe the ad away on mobile devices in order to see more of the screen and content, without the ad getting too much in the way. The new ad format lets publishers anchor the 320x50 banner ad unit to the bottom of your screen, so the ad sticks when a user scrolls. But to ensure that is not annoying to the user, the user can swipe the ad away. When the ad is swiped away it is faded away forever, that is until the user refreshes the page.
Google said, "we've started enabling this feature for a select group of publishers today, and will gradually roll it out to everyone over the coming months."
I tried this on a site that has implemented it and the swipe feels natural and it literally fades away within a second.