Bing has been experimenting with its use of site links for a while. Site links are a list of links to pages within a site that appear right below a listing within the results page. Up until now when I have seen a set of links below a listing they always appeared to be very general, but now they appear to directly related to the users search query.
This is somethign Google have been doing for quite some time, but for Bing its fairly new. I have to wonder how the Bing algo for generating the site links is different from Google.
My guess would be it reflects the search terms commonly used to access a site. For example if users frequently use the term blue widget to access a site, it would make sense to have a site link to a page titled "blue widgets" directly below the main listing in the serp. They also tend to provide the general links such as about us and contact us.