In October 2013 Google was experimenting Giant add banner. But ultimately the test has failed. I was published an article about giant banner add test on 10th October 2013. At that time Google was started experiment by selecting top branded site's ads on search result on USA. A Digital marketing company Synrgy was first discover sponsored ad when Google running this experiment on Southwest Airlines. Later Google has tested some other branded company's ads. However ultimately the experiment become unsuccessful.
Yesterday 12th March 2014 SMX West keynote discussion with Danny Sullivan about the issue. Google’s Amit Singhal said the total experiment failed and this is over.
Most probably the click-through rates (CTR) performance on giant ad banner was not better than current ad campaign. And it has no call-to-action on performance metric. On the other hand large ad banner occupied big portion of space on search engine result page. And it has no call-to-action.
Though the ad was running on USA only. For the test purpose Google was selected 30 advertisers and their ad banners was showing on about 5% of search queries. So if there hasn't changes on click-through rates (CTR) performance then running this campaign is useless. Rather advertisers can easily use current paid ad space on Search Result without investing more for ad campaign.
This is not new for Google, they have launched several product that has totally failed. Hope for the next Google will invent something new for increasing click-through rates (CTR) performance on ads.