In 2011, Bing introduced a three column layout that consists of Core Web Result, Snapshot and Social Sidebar. Through a dedicated Social Sidebar, it brings together friends, experts and enthusiasts while users are conducting a search. Users can post a question to get help from their Facebook friend. They can tag friends Bing suggests might know about the topic. Or they can simply share search and their friends can reply to the question on either Facebook or Bing.
To learn more, you can read this blog post.
I was solely assigned to the social initiative when I joined in Microsoft. The project started as an incubation project which simply shares search queries among friends. As the team became bigger, designers and engineers worked together through a lot of iterations. The project pivoted to focus more on asking related friends questions and shipped v1 in May 2012. Later, I worked with editorial team, engineers and PM to explore 50+ live experiments on improving user adoption and engagement.