For a couple of months now Google tested a new feature for the displayed ads, giving the user options to scroll between different sets of text ads (horizontal or vertical), without actually clicking on that ad or being directed to a new page. Now this feature is live and shown for every ad displayed through Google Adsense. They say this will benefit both the publisher and the advertiser, because the user interacts with the ad before clicking on a link, this way choosing what he/she is actually interested in.
When they click on the next/previous icons, the publisher doesn't receive any money (which sounds fair), however I see a possible disadvantage because this will increase the number of the pageviews for your account, so the click-through rate will actually decrease. Consider this, a user clicks three times on the next/previous icons but doesn't click on any ad, so this way your account records 3 times more pageviews lowering the click through rate. Discussable, I know, but we'll see in actual results.