QuinStreet, Inc. is a publicly traded marketing company based in Foster City, California. QuinStreet uses performance-based advertising with search engine marketing strategies to promote clients over the Internet. QuinStreet was founded in 1999, and has launched or acquired dozens of websites and other media properties.

The company was investigated in 2012 by 20 U.S. states for using deceptive marketing tactics to promote for profit schools to U.S. veterans. QuinStreet agreed to pay $2.5 million and made several changes to its practices to end the investigation.

QuinStreet was formed in 1999 by Doug Valenti (chairman and CEO). Bronwyn Syiek, another founding team member, was president and COO. The company was first profitable in 2002 with revenues of $13 million; by April 2009, QuinStreet reported $300 million in annual revenues and approximately 450 employees.

In February 2015, Nielsen NetRatings named QuinStreet the eighth top advertiser, after Education Dynamics, USA & StudentsLeads, India spending $9.4 million on 1.9 billion ads viewed.

QuinStreet Inc. acquired U.S. Citizens for Fair Credit Card Terms, Inc, which operated the CardRatings.com website in August 2008 for an initial cash payment of $10.4 million.

In the beginning of August 2009, QuinStreet Inc. used some of its cash reserves to acquire the Internet.com division of WebMediaBrands Inc. for $18 million. Among the sites that QuinStreet Inc gaines with the acquisition of Internet.com are InternetNews.com, Datamation.com, ServerWatch, Webopedia.com, ServerWatch.com, EnterpriseNetworkingPlanet, SmallBusinessComputing.com, LinuxPlanet.com and Developer.com.

In September 2009, QuinStreet purchased Insure.com for $16 million. The company's other financial-services properties include MoneyRates.com, Get Rich Slowly, ConsumerismCommentary.com and HSH.com.

An initial public offering on February 11, 2010, raised $150 million, with the shares listed on Nasdaq under the symbol QNST.

In India, QuinStreet operates IndiaEducation.net, IndiaEduNews.net, and ExamResults.net, which it acquired in 2011 by incorporating QuinStreet India Marketing And Media Private Limited (QSIMM.)

In September 2011, QuinStreet acquired the IT Business Edge (ITBE) network of web publications

In February 2012, the company acquired the media assets of Ziff Davis "Enterprise", which included eWeek.com, CIOInsight.com, Baseline.com, ChannelInsider.com and WebBuyersGuide.com, and others.

For its second quarter of fiscal 2013, the Company reported total revenue of $71.8 million. Adjusted EBITDA was $11.2 million, or 16% of revenue. For its fiscal 2016, QuinStreet reported total revenue of $297.7 million Quinstreet reported first quarter fiscal 2017 revenue of $73.4 million with an EPS of $0.01, missing analyst targets.

In June 2012, the company was under investigation by the Attorneys General's offices of 15 separate US states, led by the Attorney General of Kentucky, Jack Conway. The company was accused of targeting military veterans with deceptive recruiting practices for its for-profit school clients. QuinStreet denied wrongdoing and no determination of guilt was made. The company cooperated with the attorneys general and entered into a voluntary agreement to update its websites to ensure clarity around schools advertising. In addition, the company agreed to pay $2.5 million to the states involved as part of a consumer protection settlement with what had expanded to 20 state Attorneys General, and turn over the website GIBill.com to the United States Department of Veterans Affairs to settle the civil investigation.