Privacy Policy

Effective: January 30, 2018

Privacy Commitment

We care about your privacy and want you to be informed about what we do. This Privacy Policy explains how we collect, use, and share the information we receive about our clients and consumers and explains the options that are available to you. We’ll try to make this all as clear and as simple as possible, but if you have questions, you can contact us, and we’ll be happy to help. (See the “Contact Us” section below.)

What We Do

We have two main products: (1) Quantcast Measure and (2) Quantcast Advertise. Our Measure product is free, and it helps websites owners to understand the characteristics and demographics of the people who visit their sites. (Here’s an example.) Our Advertise product allows businesses to deliver relevant online advertising to individual consumers. For companies that want to advertise online, our Advertise product helps get their ads in front of the people that are most likely to find them interesting. For consumers, we provide ads that are most useful and relevant to their interests. And for websites, our Advertise product helps drive advertising revenue, without which the free Web we all use every day would not exist. In short, we try to make online advertising more efficient and pleasant for everyone. In order to do all this, we collect and analyze information about individual consumer interests.

Scope of this Privacy Policy

This Privacy Policy covers all of the information that we collect or receive across the Internet and mobile space through our Measure and Advertise products, as well as information we collect or receive from Visitors to our Site: (“Site”) and from Registered Users of our Measure and Advertise products. We may change this policy from time to time, so please consult the Privacy Policy regularly for updates.

Some Helpful Terminology

We use some phrases in this Privacy Policy that are unique to our business or the online advertising industry. Here are some of the key terms that you’ll need to know to make it easier to review this Privacy Policy.


A cookie is a small file containing a string of characters that is sent to your computer when you visit a website. They typically are used to store user preferences or IDs. Some cookies are set by the site you are visiting, and others are set by that site’s service partners. Cookies allow the site and services to recognize your browser. And the site or service that places a particular cookie has permission to read the contents of that cookie each time it communicates with your browser.
Important note about cookies: If you visit a site with Quantcast cookies with your browser set to accept cookies, we will assume that you have consented to our setting and reading cookies from your browser. You do not have to use cookies, but if you do not accept cookies, you may not be able to use all portions of or all functionality of the Services. In addition, some websites host prior versions of our code that used Flash cookies. We no longer use these cookies for any purpose. If you want to delete Flash cookies, please access your Flash Player settings management tool (available on Adobe’s web site), or click here.


Quantcast Tags are tiny graphics our Partners place on their web pages and lines of code they include in their apps. (In the apps, this code is called an SDK.) When a user views a site, or uses an app, with one of our Tags, our servers are notified, and we are able to collect information from the browser or mobile device.

Log Data

Log Data includes (1) information sent to us by browsers that encounter our Tags, including, for example, browser type, browser time, time of access, screen resolution, IP address, referring site URL, current site URL, and search strings; and (2) information received from the Quantcast SDK embedded in mobile apps, which may include the above as well as device identifier, location information, application data and usage information, and unique application and installation identifiers.

Personally Identifiable Information (“PII”)

Personally Identifiable Information (PII) is information about you that can be used to contact you or identify you as an individual. PII may include: your name, user name, phone number, email address, and physical address.

Non-Personally Identifiable Information (“Non-PII”)

Non-PII refers to information about individuals that, in some cases, might serve to identify a device or browser but does not identify any individual person. For example, we consider the following to be Non-PII: your ZIP code, approximate location (e.g., region, city, ZIP), your browser type, cookie IDs, device identifiers, IP address, websites you may have visited, and advertisements viewed or clicked. We also consider aggregated, de-identified, and/or anonymized data to be Non-PII. Not all jurisdictions have the same definition for PII and Non-PII. Some jurisdictions consider IP addresses to be PII. When Quantcast stores an IP address, we store it in truncated or encrypted form.

Quantcast Partners (“Partners”)

These are the site operators and mobile application developers that allow us to collect information via Tags about the visitors to their sites (and users of their apps), through either our Measure product or Advertise product.

Quantcast Services (“Services”)

This refers broadly to the entire set of services that we provide through our Measure and Advertise products, including the collection of consumer information, the analysis of that information, the provision of that information to or for our Quantcast Partners, and the selection and placement of optimal advertisements based on that information.

Information Collection and Use

Information Collected from the Quantcast Site

When you visit, whether as a Visitor or a Registered User, our servers record and collect Log Data automatically sent by your browser. We use the Log Data to monitor, analyze, administer, and improve the Quantcast Site and our Services. We require our Quantcast Partners to provide some PII as part of signing up to use our Measure and Advertise products, such as full name, contact email, physical address, and telephone number. We use this PII mainly to provide the Services, to administer accounts, and to address questions and issues you might have.

If you contact us by email, we may keep a record of your contact information and correspondence. If you provide contact information to us, we may use that information to contact you with Quantcast newsletters, marketing, or promotional materials. If you decide at any time that you no longer wish to receive such communications from us, please follow the unsubscribe instructions provided in any of the communications.

Information Collected through our Services

When you visit a site or app operated by a Quantcast Partner, the Partner permits us to collect Log Data (defined above); we also receive non-PII directly from our partners. We associate that information with a unique random identifier (your cookie ID), not with your name, email, address, or phone number. We use this information to help improve the accuracy of our Measure product (discussed above) and to determine what advertisements might be interesting to you.  For example, if you were recently searching for plane tickets to San Francisco, we might predict that you would be interested in purchasing a nice warm sweater, and then show you an ad from one of our Advertising clients that sells sweaters.  (Technically, to be more precise, we would predict that your identifier might belong to a person interested in sweaters, because we don’t know who you are.)

Information Sharing and Disclosure

Personally Identifiable Information

We will not share or disclose your PII to any third party, except as requested by you or as discussed below in the section on information shared with our service providers.

Non-Personally Identifiable Information

We may share with third parties Non-PII, including certain Log Data, as part of providing and improving our Measure and Advertise products. For example, we may disclose such data to companies involved in ad delivery or ad visibility. Likewise, we may disclose such data in order to provide or facilitate site audience measurement, traffic analysis, or demographic analysis, and to enable websites to provide their advertisers with audience segments that are appropriate for their products or services.

Information Shared with Our Service Providers

We may use third parties and Quantcast affiliate companies to help us administer and improve our Measure and Advertise products. For example, these companies may assist with hosting, data processing, database management, and administrative tasks. These third parties and affiliates may have access to your PII (if you submitted such data to Quantcast) and Log Data, but only to perform these tasks on our behalf, and they are obligated not to disclose or use it for any other purpose.
We also receive Demographics and Interest Reporting data about the Quantcast Site from one of our service providers, Google Analytics. This data is used purely to satisfy our own curiosity about the type and quality of Demographic and Interest Reporting that Google provides. If you like, you can opt out of Google Analytics through Google’s Ad Settings.

Information Disclosed for Our Protection and the Protection of Others

It is our policy to protect you from having your privacy violated through abuse of the legal system. But we reserve the right to disclose information about you to government or law enforcement officials or private parties as we, in our sole discretion, believe necessary: (i) to comply with any applicable laws, regulations, and valid subpoenas, warrants, and court orders; (ii) to protect the rights, property, and safety of ourselves, third parties, or the public in general; and (iii) to prevent or stop activity we consider to be illegal or unethical.

Information Disclosed in a Change of Ownership

Quantcast may sell, transfer, or otherwise share some or all of its assets, including your PII and Log Data, in connection with a merger, acquisition, reorganization, or sale of assets or in the event of bankruptcy. We may also make certain PII or Log Data available to a potential investor or purchaser (and their advisers) in advance of any such transaction completion.

Data Combination

We do not link Log Data to your name, address, email, or phone number, or otherwise attempt to discover your identity. We employ appropriate organizational and technical security safeguards to keep your Log Data secure and to prevent it from being related to your PII.

Cross-Platform Associations

We provide a cross-platform reporting service to Partners that operate both websites and mobile apps. To accomplish this, we rely on hashed (i.e., scrambled) identifiers derived from user logins to associate your usage across mobile and desktop platforms. This allows our Measure product to provide meaningful reports across platforms for a single Partner. We also sometimes rely on Log Data to make cross-platform associations.

Data Retention Policy

We retain Log Data for 13 months to accommodate seasonality. It is then permanently deleted. This is the longest period of time that we will retain the Log Data we collect through our Measure and Advertise products.

How to Opt Out

If you prefer not to receive interest-based content and ads enabled by Quantcast, you can opt-out by clicking on the Quantcast “Opt Out” link here. Additionally, we are a member of the Network Advertising Initiative (NAI) and participate in the Digital Advertising Alliance’s (DAA) Self-Regulatory Program. Each of these programs provides an opt-out feature where consumers can choose not to receive targeted advertising from any NAI or DAA affiliate. These links will take you to the NAI opt out and the DAA opt out. If you are located in the European Union, you may prefer to use the EDAA opt out. After you opt-out, we will place a cookie on your browser that identifies you as having opted out. Then you will not receive interest-based content or advertisements enabled by Quantcast and we will not log your pattern of website visits or other online media consumption.  Because our opt-out is cookie-based, your browser must be set to accept third party cookies. If you use multiple devices or browsers, you’ll have to opt out on each. If you delete the cookie, you will need to opt-out again.

Accessing, Changing, or Deleting Your Information

You have a right to access your PII controlled by Quantcast by emailing us at the relevant email address identified in the “Contact Us” Section of this Privacy Policy. We reserve the right (subject to applicable law) to decline requests that are disproportionate or may jeopardize the privacy of others. If you are a Registered User, you may review, update, correct, or delete the PII in your registration profile by logging into your account. Log Data cannot be amended or deleted by you. If you want to delete your account, please contact us. We may retain an archived copy of your records as required by law or for so long as is necessary in light of the purposes for which such records were collected or legitimately further processed.

Data Security

We employ administrative, physical, and technical measures designed to protect your information from unauthorized access. These measures may include encryption of information you provide and employment of information storage security technologies to block access from outside our network. Please be aware that no method of transmitting information over the Internet or storing information is completely secure. Additionally, in some instances our Partners or others may provide information to us in unencrypted form.

International Transfers

Your Log Data and PII may be transferred to, and maintained on, computers located outside of your state, province, country (etc.), where the privacy laws may not be as protective as those in your jurisdiction. If you are located outside the United States and choose to provide information to Quantcast, please be advised that we transfer PII to the United States and process it there. Your consent to this Privacy Policy, followed by your submission of such information, represents your agreement to that transfer.

Our Policy Toward Children

Quantcast does not knowingly collect PII from children under 13. If a parent or guardian becomes aware that his or her child has provided us with PII without their consent, he or she should contact us. If we become aware that a child under 13 has provided us with PII, we will delete such information from our files.

Health Information

Quantcast does not knowingly collect or utilize any sensitive health-related information, such as, for example, information related to past or present medical conditions or prescriptions. We do assist some of our advertising clients in serving ads for their health, medical, and wellness related products. We also provide the following standard segments related to health and wellness: cosmetics, diapers, hair care, and mouthwash.

Other Websites and Apps

We contractually require our Quantcast Partners to ensure that their sites and apps containing Quantcast Tags post adequate privacy policies and otherwise protect the privacy rights of their visitors. However, the fact that we link to a particular site or app or receive data from a site or app, does not mean that we endorse that site or app, nor its privacy practices. These other websites have their own terms of use and privacy policies, and we would encourage you to read those terms and policies when you visit those websites.

Quantcast Data Control

The Site and Services are made available and provided to persons residing within the United States by Quantcast Corporation, located at 795 Folsom Street, San Francisco, CA 94107. Information or data relating to persons within the United States provided to or gathered by the Site or Services are controlled by Quantcast Corporation.

The Site and Services are made available to persons resident outside the United States by Quantcast International Limited, located at Beaux Lane House, Lower Mercer Street, 1st Floor, Dublin 2, Ireland. Information or data relating to persons resident outside the United States provided to or gathered by the Site or Services is controlled by Quantcast International Limited.

Our Memberships and Affiliations

Quantcast is an active member of industry associations that govern the policies around online consumer privacy in the context of internet-based advertising, including: the Network Advertising Initiative (NAI), the Digital Advertising Alliance (DAA), and the European Interactive Digital Advertising Alliance (EDAA). Quantcast complies with the NAI Codes of Conduct, the DAA Self-Regulatory Principles, and the EDAA Self-Regulatory Principles. We believe that these codes and principles help protect consumer privacy.

Please see the “Opt Out” section of this Privacy Policy for more information about the NAI’s, DAA’s, and EDAA’s opt-out pages.

Changes to the Privacy Policy

Any information that we collect is subject to the privacy policy in effect at the time that information is collected. However, we may revise this Privacy Policy from time to time. If we make any material changes to this Privacy Policy, we’ll notify you of those changes by posting them clearly on our website or by sending you an email or other notification, and we’ll indicate when such changes will become effective.

Contact Us

If you have any questions about this Privacy Policy, please let us know.

Persons in the United States, please contact:

Quantcast Corp.
795 Folsom Street
San Francisco, CA 94107
Attn: Legal Department

Persons outside of the United States, please contact:

Quantcast International Limited
Beaux Lane House
Lower Mercer Street, 1st Floor
Dublin 2, Ireland

If you have contacted us about a privacy or data use concern and feel that we have not addressed it satisfactorily, you may contact our US-based third party dispute resolution provider (free of charge) at