This is a cute user interface test from Bing, where when you hover your mouse cursor over the title of a search result snippet, it then shows the favicon of the site on the left of that title.
This was spotted by Frank Sandtmann, who shares things with me all the time via email and is sadly not on Twitter. He made this GIF of it in action for me – you can click on it to enlarge it:
I think it is cute.
Frank is always finding new things with Bing by the way.
Forum discussion at Twitter.