Yahoo is testing a new search interface. The new interface moves the Yahoo logo from the left side of the search box, all the way to the right side. It also adds a menu to the right that opens various new options from Yahoo. Finally, the search button is blue instead of purple.

The image on the top is the test and the image directly below is the one most searches see on Yahoo, this way you can see it side by side. You can also click to enlarge: