Yahoo is testing a new “Official Site” tag on their ads, to denote when a site is advertising is an official site, rather than a partner or reseller.

Here it is in action:

When you mouseover it, however, it changes to red instead.

These only seem to trigger when you do a brand search for the company’s name.  They don’t show up when you search for other keywords that also bring up the ad.

This is likely a Bing Ads related feature that is being displayed in the search ads on Yahoo Search.  Bing also began testing their own version of “Official Site” tags in search ads, but they were in text and more unobtrusive when compared to the Yahoo version.

Here is how Bing’s version looks:

Bing does not consistently show the “Official Site” tag in their search ads, and Yahoo seems to be testing it on a small percentage of searches as well.