Ad refresh for screen orientation changes: If your responsive page changes its layout following a screen orientation change (e.g., when a tablet or phone goes from portrait to landscape), we’ll request and load a new ad to fit the new page layout.
Smart sizing based on the space available: Our ad code will now automatically adapt all newly created responsive ad units to fit your page layout. All existing responsive ad units that have their width and height explicitly specified via CSS will continue to function as before. Please see our Help Center for information on switching to the smart sizing mode.
Reporting by ad size served: To better understand the mix of ad sizes served by your responsive ad units, your ad unit reports can now be broken out by the size of the ad served.