graeme_p - 11:12 am on Oct 4, 2011 (gmt 0)
Web surfers will find the circular-style advertising, which shows multiple pictures and large type, by clicking on search ads.
So they are not a new ad format. They are what you see when you click on an ad. That also explains the high click-through rates: People seeing these will already have clicked on an ad, so they are likely to click again for more information or to buy.