The ad units are much larger than your normal 468×60 banners, but rely heavily on user interaction–meaning, you have to “roll over” the ads before they expand. Here’s a screen grab of what we assume is one of the new ad units (taken from BusinessWeek):
Here’s how BW explains the new ad formats:
The three new ad units are all bigger than standard display ads, and potentially they’ll be the only ad on the first screen. They also will be more interactive, even allowing viewers to bookmark them like they do Web pages so they can come back to them. They include a “Fixed Panel” that’s 336 pixels wide and 860 pixels tall and scrolls to the top and bottom of a page as the user scrolls; an “XXL Box” that’s 468 by 648 pixels, featuring the ability to embed video; and a huge 970-by-418-pixel “Pushdown” ad that opens up and then rolls up to the top of the page.
So hold on to your pixels, the next generation of display ads are going to gobble-up as much real estate as they can!