The display resembles a mini (Google) Knowledge Graph, with small image thumbnails and descriptions appearing to the right of the text suggestions. The feature smartly uses the area that would generally be blank in the drop-down area below the search box. The designers appear to have correctly assumed that the named entity suggestions would occur generally on shorter queries, so there's room for the display.
Right facing angle brackets appear to the right of the text suggestions as you type and indicate which queries will produce the categorized results... either unique named entities or multiple entities for the same name which need disambiguation. I notice some results are pulled from freebase.com.
Clearly, Bing and Google are drawing "inspiration" from the other's entity/Knowledge Graph displays. This one's a +1 for Bing. I'm wondering how closely Google might follow with something similar.