Yahoo is running a heart border along the left side of search ads in their search results for Valentine's Day. They're hoping that the hearts will bring more attention to the ads and increase clicks and conversions.
So far, I've only been able to get the heart border to show up on a search for the exact term "Valentine's Day." Add flowers or candy and no hearts appear. If the hearts really do increase clicks and conversions, it would seem a good idea to run the hearts along those broader searches as well.