If you've been to any of my talks recently you'll know that I'm continually banging on about the fact that search is becoming far more social than it has ever been in the past, and that it will continue to do so in the future. The role and the importance of the individual in +1ing things, or 'Liking' them on Facebook, or blogging about them and so on. Google is increasingly using social markers to affect the ranking of the results that you get if you're logging in when you search.
Bing has also stepped up its game with Bing Social for example. They have also included a new pane in the search results that talks about 'People who know', slightly similar to the links to people that Google pulls from G+. Unfortunately this isn't yet available in the most of the world - it still seems pretty much limited to the US, so I have had to steal a visual from the ever wonderful SearchEngineWatch to illustrate what they're up to.
You can see that there is a listing of people, an opportunity to connect with your Facebook account to see what your friends and colleagues think about something, and links through to Klout and Twitter. Moreover, the sidebar also includes (as appropriate) friend tagging, photo searching, and data from Q&A site Quora.