Bing has started to roll out social search to a small subset of users (US) and queries – so you may or may not see it appearing on your search results page. The team plans to make the feature available to all US users within a short period.
Bing Social Search pulls in social content generated on Twitter to surface the most relevant updates within seconds of a breaking news event.
At Bing, we analyze what topics are generating the most interest on Twitter to bring you the latest and most interesting content. So if you wanted to find out more information on the just-announced Kin phone from Microsoft, you’ll be able to discover it on Bing as the announcement was being made and journalists started tweeting about the product.
Lawrence Kim also tells they are using Twitter data to show the most popular shared links for navigational queries. Example: if you are looking for most popular celebrity news on TMZ, Bing will show you the most shared links on Twitter.
These features are part of the Spring updates.