The story
Founded by Udi Manber in 2004.1
A9, a subsidiary of Amazon.com, was founded in 2003 with an exclusive focus on producing technology for search and advertising. Initially located in the Wells Fargo building on Hamilton Avenue, in 2004 they moved into the building previously used by the DEC Systems Research Center in Palo Alto, California. One purpose of A9.com was to leverage algorithms, and the name was chosen as a numeronym to represent that word (i.e. 'A' + 9 other letters). The office was in Silicon Valley, near Stanford University. Under the direction of its first president, Udi Manber, A9 focused on several areas, including the A9.com destination website, a browser toolbar, product search, and a search advertising platform. Some early A9 services such as "search inside the book" continued, while others have been discontinued. The A9 search engine powered product search for Amazon.com and several other eCommerce retailers.
In February 2006, Manber resigned to move to Google and was replaced by David L. Tennenhouse as president. In September 2006, William Stasior, one of A9's founders and a former AltaVista and Amazon.com executive, was named president. In June 2009, A9 acquired SnapTell, which developed smartphone-based visual search applications.
Stasior left in October 2012 to join Apple Inc. to work on Siri. Brian Pinkerton, who had developed WebCrawler in the 1990s, became general manager of A9 in 2012.
Brian Pinkerton was replace by Srikanth Thirumalai, who left when A9 became Amazon Search.
In 2019, after reporting from The Wall Street Journal revealed that Amazon had changed its search algorithm to favor more profitable products, Amazon took down the A9.com site and pointed the domain name to Amazon's home page.
From Wikipedia’s article on A9.com, shared under CC BY-SA 4.0.4