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. Despite the sanctions, as late as 2016 QuinStreet continued gathering information which it sold to for-profit colleges.
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 gained with the acquisition of Internet.com were 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.
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.
In 2018, the company acquired AmOne, an online marketing company. In 2019, Quinstreet acquired CloudControlMedia, LLC and MyBankTracker.com, LLC.
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. For its fiscal year ending June 30, 2018, QuinStreet reported net revenue of $404 million and basic net income per share of $0.34. Net revenue for fiscal year ending June 30, 2019, was reported to be $455 million with basic net income per share of $1.26.