Microsoft is testing zoomable and sticky related searches in the Bing Search results page. So one variation has the related searches stick to the right top of the screen as you scroll and the other will zoom into the related search, as you hover your mouse cursor over the feature.
While Bing may never catch up to Google in search engine market share, it has the upper hand when it comes to Related Searches usage. The difference is placement: top-left (where users naturally scan) versus bottom-of-page (where few users scroll).