Bing is testing a new search results feature where they add an icon as you hover either the search ads or organic results. The icon is an open in new window or new tab icon, it is in the form of a box with an arrow.
Jennifer Slegg covered it first and also posted about it on Twitter. Here are screen shots she shared of it on Bing Ads and organic Bing results:
Of course you can also go to your Bing search settings and enable all search results to open in a new window or you can use a control click and now, maybe this new icon – if you see it.
Forum discussion at Twitter.