Merchant Promotions by Bing is being rolled out of pilot in the US, and gives advertisers a way to highlight offers in their product ads.
As long as Merchant Promotions are actives, ads will appear with a “Special Offer” extension. If users click on this notice, an offer will pop up, including a description, promotional code, expiration date and a link to shop the product.
If you want to get reporting detail on Merchant Promotions, select Click Type ID and Total Clicks on Ad Elements in the product partition and product dimensions reports in Big Ads.
See the blog post announcing the rollout for more details.