Twitter: @addthis
Facebook: AddThis
Founder: Hooman Radfar, Dom Vonarburg


AddThis is a content engagement platform that offers tools to drive web traffic to social media pages and provides data on the corresponding stats. The platform lets web publishers include sharing and following widgets on their websites. AddThis has several free tools for small web publishers as well as a paid professional suite of more sophisticated tools.


Headquartered in Vienna, VA, AddThis was founded by Hooman Radfar and Dom Vonarburg. In 2013, AddThis reached around one trillion social media views, 1.6 billions social users, 14 million domains and more than 300 services globally for 2013. [5] In 2014, the company launched AddThisPro, a professional audience targeting tool that allows user websites to customize a user's ad experience based on their browser history, access device and personal interests. This enables marketers to tailor their messages for the audience they want to reach.  AddThisPro offers more tools and greater dashboard control over content widgets, and includes a suite of tools for promotion and analytics of a website. [2] The company's CEO, Richard Harris, said the company plans to release more new tools next year to offer more deeper insights into the data for its 14 million+ user websites. [4]  As of 2014, AddThis had reached over 97% of web traffic in the US; gobally, the company is used by over 14 million websites reaching over 1.6 billion readers. In 2014 the company also began offering its professional suite of tools on a subscription-based model. [3]

Funding rounds

Funding RoundDatePaper AmountInvestors
Secondary MarketSep 2014Undisclosed AmountSharesPost Investment Management
Private EquityOct 31, 2011$17 million
Series DMay 10, 2011$20 millionInstitutional Venture Partners (IVP), Novak Biddle Venture Partners, New Enterprise Associates, Nigel Morris, Ron Conway, Ted Leonsis, QED Investors, Steve Case, Revolution LLC
Series CMay 20, 2008$18 millionQED Investors, Novak Biddle Venture Partners, New Enterprise Associates
Series BJuly 27, 2007$10 millionSignatures Capital, Bobby Yazdani, Amidzad Partners, SV Angel
Series BFeb 1, 2007$5.5 millionRevolution LLC, Steve Case, Ted Leonsis, Novak Biddle Venture Partners, ZG Ventures, Mark Jung
Series AMay 1, 2006$2.5 millionNovak Biddle Venture Partners, ZG Ventures


  1. Lalita Clozel "AddThis cofounder becomes Expa entrepreneur-in-residence" September 26, 2014

  2. Eric Hal Schwartz "Vienna-based AddThis Now Offers $12/Month Pro Platform" DCInno February 12, 2014

  3. Kira M Newman "Under New CEO, DC-Based AddThis Launches AddThis Pro" Tech Cocktail February 12, 2014

  4. Lalita Clozel "AddThis releases audience targeting tool" December 3 2014

  5. Billy Mitchell "AddThis' Data Shows New Progressions in Social Sharing" DCInno December 20, 2013