Reference.com was launched by InReference, Inc in February, 1997. The site was later acquired by Lexico Publishing Group, LLC. In 2005, Lexico announced that Reference.com would begin offering searches of Wikipedia content. In mid-2007, the site typically ranked in the mid-200s among the most popular websites on the Internet. The popularity of Dictionary.com had been greatly boosted by Google's practice of offering a link at the top of their search results that go to the Dictionary.com definition. This exclusive relationship was terminated without explanation to the public when the Google links were redirected to definitions at Answers.com. (In December of 2009, the Answers.com links were replaced with Google's own dictionary.) Google additionally added a Dictionary.com definition link for certain search words in a non-exclusive relationship (along with links to definitions from a few other commercial reference websites). On 3 July 2008, IAC acquired Lexico Publishing Group, LLC and its three properties: Thesaurus.com, Reference.com, and Dictionary.com.
Reference.com reproduces content from external sources. The site's sources include other online dictionaries, encyclopedias, and a search of terms found on other websites such as Wikipedia and the CIA World Factbook. The site can also search Usenet groups and other mailing lists.
Reference.com in 2010 topped the list compiled by The Wall Street Journal ranking websites by how many third-party tracking cookies were added to the user's computer. Reference.com added 234 tracking cookies when encountering a first-time user.
^"Tracking The Companies That Track You Online". Fresh Air. August 19, 2010. Retrieved 2010-09-14. "The one site that installed the most was Dictionary.com. A visit to Dictionary.com resulted in 234 trackers being installed on our test computer, and only 11 of those were installed by Dictionary.com. ... So on Dictionary.com, the vast majority of the trackers (200 out of 234) were installed by companies that the person visiting the site probably had never heard of.""