Microsoft Bing (before called Windows Live Search and MSN Search) is a search engine. Microsoft calls it a "decision engine", meaning that Bing tries to interpret search queries and give people better search results compared to a typical search engine, helping the user make better decisions. Bing concentrates on four major areas: shopping, travel, local and health. A preview version was made available for everyone to use on June 1, 2009, and the website was fully launched on June 3, 2009. The website quickly became popular after a few weeks.

On July 29, 2009, Microsoft and Yahoo! announced that Bing would power Yahoo! Search. All Yahoo! Search global customers and partners will be shifted to Bing by early 2012.

In October 2011, Microsoft announced "Tiger", a new internal search computer program for Bing. When it was finished, Bing delivered faster and more relevant search results for users. It has been incorporated into Bing since August 2011.