The Huffington Post was founded by Arianna Huffington, Andrew Breitbart, Kenneth Lerer, and Jonah Peretti on May 9, 2005. It has an active community, with over one million comments made on the site each month.
Prior to The Huffington Post, Huffington hosted the website Ariannaonline.com. Her first foray into the Internet was the website Resignation.com, which called for the resignation of President Bill Clinton and was a rallying place for conservatives opposing Clinton.
In August 2016, Arianna Huffington stepped down from her longtime role as editor-in-chief to pursue other ventures, and in December of that year was officially succeeded by Lydia Polgreen.
In April 2017, Polgreen announced the company would rebrand, changing its name to HuffPost and unveiling significant changes to the design of its website and logo. Polgreen also stated that the redesign would be accompanied by changes in the site's content and reporting.
In approximately June 2007, the site launched its first local version, HuffPost Chicago. In June 2009, HuffPost New York was launched, followed shortly by HuffPost Denver which launched on September 15, 2009, and HuffPost Los Angeles which launched on December 2, 2009. In 2011, three new regional editions were launched: HuffPost San Francisco on July 12, HuffPost Detroit, on November 17, and HuffPost Miami in November. HuffPost Hawaii was launched in collaboration with the online investigative reporting and public affairs news service Honolulu Civil Beat on September 4, 2013.
The Huffington Post launched its first international edition, HuffPost Canada, on May 26, 2011. On July 6 of the same year, the Huffington Post UK launched its UK edition. On January 23, 2012, Huffington, in partnership with Le Monde and Les Nouvelles Editions Indépendantes, launched Le Huffington Post, and the launch of French-language edition is the first in a non-English speaking country. On February 8, another French language edition was launched in the Canadian province of Quebec. On May Day, a U.S.-based Spanish-language edition was launched under the name HuffPost Voces, replacing AOL's Hispanic news platform, AOL Latino. The following month an edition for Spain was announced, as was one for Germany. On September 24, an Italian edition, L'Huffington Post, was launched, directed by journalist Lucia Annunziata in collaboration with the media company Gruppo Editoriale L'Espresso. On May 6, 2013, an edition for Japan was launched with the collaboration of The Asahi Shimbun, the first edition in an Asian country. With the launch of Al Huffington Post, there is a third francophone edition, this time for the Maghreb area. On October 10, Munich-based Huffington Post Deutschland has been put online in cooperation with the liberal-conservative magazine Focus, covering German-speaking Europe. In January 2014, Arianna Huffington and Nicolas Berggruen announced the launch of the WorldPost, created in partnership with the Berggruen Institute. Its contributors have included former British prime minister Tony Blair, Google CEO Eric Schmidt, novelist Jonathan Franzen and musician Yo-Yo Ma. On January 29, 2014, the Brazilian version was launched as Brasil Post, in partnership with Abril Group, the first in Latin America. In September 2014, The Huffington Post announced they will launch in Greece, India, and introduce HuffPost Arabi, an Arabic version of the website. On August 18, 2015, HuffPost Australia was launched. The Huffington Post planned to launch a Chinese version in 2015. Due to strict media controls, the content of Chinese version would not include serious news report, only entertainment and lifestyle. On November 21, 2016, HuffPost South Africa was launched, the brand’s first sub-Saharan edition. In April 2017, HuffPost South Africa was directed by the press ombud to apologise unreservedly for publishing and later defending a column calling for disenfranchisement of white men which was declared malicious, inaccurate and discriminatory hate speech..
In 2011, after its purchase by AOL, The Huffington Post subsumed many of AOL's Voices properties (including AOL Black Voices, which had originally independently established in 1995 as Blackvoices.com, and AOL Latino). The Voices brand was expanded in September 2011 with the launch of Gay Voices, a vertical dedicated to LGBT-relevant articles. Other established sections, such as Impact (launched in 2010 as a partnership between Huffington Post and Causecast), Women, Teen, College, Religion, and the Spanish-language Voces (en español) are also sorted under the Voices meta-vertical.
By late 2013, however, The Huffington Post was taking steps to operate as more of a "stand-alone business" within AOL, taking control of more of its own business and advertising operations, and directing more effort towards securing "premium advertising".