MSN Search was launched in the third quarter of 1998, using search results from Inktomi. One year later, they started using search results from other engines like Looksmart and Altavista. In 2004, Microsoft made their own search system for MSN Search.
Windows Live Search
The first public beta of Windows Live Search was unveiled on March 8, 2006, with the final release on September 11, 2006, replacing MSN Search.
On March 21, 2007, Microsoft announced that it would separate its search developments from the Windows Live services family, rebranding the service as Live Search.
In 2008, Microsoft recognized that there would be a brand issue as long as the word "Live" remained in the name. To create a new identity for Microsoft's search services, Live Search was officially replaced by Bing on June 3, 2009. Brand New ranked this the worst logo of 2009.
Just a few months before the new logo came out, another logo was unveiled on April 29, 2013, at the Design Day 2013 event. The logo can be seen here, at 30:18.
Bing revealed a new logo on September 17, 2013, and was rolled out in the following weeks. It was still used on the website for a short time after the 2016 logo was introduced.
A new Bing logo was launched on January 14, 2016, and used in tandem with the previous logo until February 2016. It is very similar to the 2013 logo. The logo is still seen on error messages for Bing.
A new logo influenced by Microsoft's Fluent Design language was used for testing throughout 2020, A blue logo appeared on search results was also used. This logo was only used for two days from April 1, 2020, and the previous logo went back into use on April 3, 2020.
On August 1, 2020, this logo appeared for a short time on Bing's website for testing purposes. Microsoft officially announced the new name, Microsoft Bing, and logo on October 5, 2020. The rebrand took place the same day. The 2020 blue logo is also now officially used, replacing the 2016 logo. (see Microsoft Bing/Icons) The new logo used Microsoft's 2012 logo including the four squares (which represent Microsoft's products, Office, Xbox, Windows, and Bing). The Bing wordmark was boldened and was colored gray so that it could match the variation of Segoe UI that is used on the Microsoft Logo.