Bing have is moving away from the minimalist search result interface and started integrating a lot in the search engine results. And as I have seen their presentations in various conferences, they back up their search results layout that has categories on the side with eye tracking heat map data and other user testing saying that these categories really help users get to what they are searching for. Google might consider this as well. Right now there are tons of posts talking about the preview of Google’s new search result interface showing a side bar. It does not seem to be categories, but just repositioning the Web, Images, Video, News, etc options from the top to the side.