The new Bing has a three column design with Core Search, Snapshot & Sidebar panes. Core Search contains core web results which will help get results easier without cluttering it with social updates. Snapshot is the center column. It is between the web results on the left and the new sidebar on the right. Snapshot has info and services related to your search along with maps, reviews & others. This helps the users to take the intended actions. Sidebar is all about social information with info from friends, experts & others. Social results which were in core part have been completely moved to sidebar. With the rise of social media, social results appearing along with main search results has added new dimension to search results.
Search engines have been intorducing new features regularly over the years to provide more accurate & fresh results to users. Integrating social search results help provide real time information. Also search engines have been tweaking their algorithms to keep spam, low quality sites away from the results. So the websites should adhare to the new guidelines & also fresh/updated content to get higher rankings in search.