United States: FTC Highlights Third-Party Report Finding That Companies Are Hiding The Ball On Cross-Device Tracking

Earlier this month, the FTC announced that a third-party study and report on cross-device tracking had been completed by the Office of Technology, Research and Investigation ("OTech"), following up on their presentation on this topic at the FTC's 2015 workshop.  The FTC released its own report on cross-device tracking last week, which will be covered in a subsequent blog post.  OTech's study focused on: 1) what information companies are collecting and may be using to track consumers across devices, and 2) what companies are disclosing about their cross-device tracking in privacy policies or otherwise (the answer is not much!). 

OTech's report underscores the fact that, while increasingly sophisticated data tracking and matching technologies are being developed and used regularly by those in digital advertising, the data subjects (i.e., regular consumers like you and me, who browse the internet across multiple devices) are often kept in the dark about how their data is used and tracked for these purposes.  OTech's study, along with the FTC's 2015 workshop and their own recently released staff report, make clear that this is an area of concern for government regulators, not to mention other self-regulatory bodies in this space –  notably, the Digital Advertising Alliance plans to enforce its 2015 guidance on cross-device tracking for its members beginning in February 2017.  Read on to see what steps companies should be taking to ensure they comply with the latest best practices on cross-device tracking, as per the OTech report.

Taking a Step Back... What is Cross-Device Tracking and Why Do Advertisers Use It?

Cross-device tracking is the practice of tracking and identifying web users across multiple devices.  Or, put another way, cross-device tracking involves the collection, sharing, and matching of data gathered from multiple internet-connected devices (phone, desktop computer, tablet, smartTV, etc.), in order to confirm that those devices are being used by the same person.

This tracking can be used to generate a detailed profile about a particular user's online behavior across multiple devices.  Advertisers, in particular, find this information valuable for market research, retargeting ads to consumers based on their specific preferences and interests, and measuring conversion rates across devices (i.e., measuring those instances where a particular consumer clicks on an ad on one device and then makes a related purchase on another device).

There are two widely-recognized types of cross-device tracking: Deterministic and probabilistic.

  • Deterministic cross-device tracking is when users are asked to log in to websites and apps on every device they use. This allows the operators of those platforms to track their users across devices, linking the devices to a single user account with the same login information. Examples include Facebook, Twitter and Google, which require users to log in no matter what device is used to access those platforms.
  • Probabilistic cross-device tracking involves the collection and use of various data points, such as device type, operating system, IP address, location services, and browsing history, to link multiple devices to a single user, based on predictive algorithms that take into account typical patterns of consumer engagement with multiple devices. Probabilistic tracking can be more concerning from a privacy perspective because, as the FTC noted in connection with its 2015 workshop, it's "generally invisible to consumers, and unlike tracking through cookies, the consumer has no ability to control it."

The OTech Study – What It Found and What It Didn't 

As part of its study, OTech visited the top 20 sites for news, sports, shopping, games and reference (100 sites total) on two different devices to determine what information was being collected and shared across the two devices.

Here's what they found: While there was no definitive evidence that companies observed in the study were engaged in cross-device tracking, they had the capacity to do so.  The visited websites collected and shared with other third-party sites all kinds of information that would allow them to track user behavior across the different devices, as demonstrated in the findings below.

  • 861 third-party domains collected data on both devices, including domains associated with companies who specialize in probabilistic cross-device linking
  • 106 third-party domains shared unique, browser-specific cookie identifiers with 210 other third-party firms including dedicated cross-device tracking companies
  • At least 16 of the 100 sites reviewed shared personally identifiable information — or hashed personally identifiable information – including email addresses or user names — with 60 different third-party domains.

Here's what they didn't find: Despite the figures listed above, many of which suggest cross-device tracking was likely happening, there was barely any disclosure of such tracking in the companies' applicable privacy policies.

The report notes that the privacy policies for the websites it observed "contained little explicit discussion of cross-device tracking specifically, or whether consumers had the ability to turn off cross-device linkage."  Of the 100 websites assessed, OTech found that just three provided any information about enabling third-party cross-device tracking.

The Takeaways

As cross-device tracking technologies become more sophisticated, advertisers will rely on such technologies with increasing frequency to create and serve more effective and innovative advertising.  The FTC's workshop and this third-party study demonstrate, however, that regulators consider cross-device tracking to be a potential minefield for privacy concerns, both because the technology is becoming more complicated and because consumers have limited visibility into how it works and when it's even being used.  Those in the digital advertising space should take heed of this report and the DAA's guidance by applying the core privacy principles of transparency, notice, and choice to these practices.

In particular, advertisers and related parties engaged in cross-device tracking should:

Be Transparent and Provide Notice 

  • Clearly disclose in privacy policies whether they (or any third parties with whom they share information) are engaged in cross-device tracking and how such "device-aggregated" data is being used;
  • Consider updating agreements with clients and service providers to ensure they have disclosures on cross-device tracking in their privacy policies

Give Users Choices and Honor Their Preferences

  • Tell users in privacy policies (or other notifications, if applicable) how they can opt-out of device linkage, including by providing links to any third-party sites where consumers can indicate these preferences. For users, this could involve the laborious process of opting out on each of their devices and browsers and checking regularly to ensure those preferences are maintained.
  • Honor consumer opt-outs across all devices associated with that user. This means that if a user opts out of cross-device tracking on one device, data collected from that device should not be used to serve them ads (or for any other purpose) on any of their other devices, or shared with unaffiliated third parties.


This post first appeared in Frankfurt Kurnit's Focus on the Data blog (www.focusonthedata.com). It provides general coverage of its subject area. We provide it with the understanding that Frankfurt Kurnit Klein & Selz is not engaged herein in rendering legal advice, and shall not be liable for any damages resulting from any error, inaccuracy, or omission. Our attorneys practice law only in jurisdictions in which they are properly authorized to do so. We do not seek to represent clients in other jurisdictions.

To print this article, all you need is to be registered on Mondaq.com.

Click to Login as an existing user or Register so you can print this article.

In association with
Related Video
Up-coming Events Search
Font Size:
Mondaq on Twitter
Register for Access and our Free Biweekly Alert for
This service is completely free. Access 250,000 archived articles from 100+ countries and get a personalised email twice a week covering developments (and yes, our lawyers like to think you’ve read our Disclaimer).
Email Address
Company Name
Confirm Password
Mondaq Topics -- Select your Interests
 Law Performance
 Law Practice
 Media & IT
 Real Estate
 Wealth Mgt
Asia Pacific
European Union
Latin America
Middle East
United States
Worldwide Updates
Check to state you have read and
agree to our Terms and Conditions

Terms & Conditions and Privacy Statement

Mondaq.com (the Website) is owned and managed by Mondaq Ltd and as a user you are granted a non-exclusive, revocable license to access the Website under its terms and conditions of use. Your use of the Website constitutes your agreement to the following terms and conditions of use. Mondaq Ltd may terminate your use of the Website if you are in breach of these terms and conditions or if Mondaq Ltd decides to terminate your license of use for whatever reason.

Use of www.mondaq.com

You may use the Website but are required to register as a user if you wish to read the full text of the content and articles available (the Content). You may not modify, publish, transmit, transfer or sell, reproduce, create derivative works from, distribute, perform, link, display, or in any way exploit any of the Content, in whole or in part, except as expressly permitted in these terms & conditions or with the prior written consent of Mondaq Ltd. You may not use electronic or other means to extract details or information about Mondaq.com’s content, users or contributors in order to offer them any services or products which compete directly or indirectly with Mondaq Ltd’s services and products.


Mondaq Ltd and/or its respective suppliers make no representations about the suitability of the information contained in the documents and related graphics published on this server for any purpose. All such documents and related graphics are provided "as is" without warranty of any kind. Mondaq Ltd and/or its respective suppliers hereby disclaim all warranties and conditions with regard to this information, including all implied warranties and conditions of merchantability, fitness for a particular purpose, title and non-infringement. In no event shall Mondaq Ltd and/or its respective suppliers be liable for any special, indirect or consequential damages or any damages whatsoever resulting from loss of use, data or profits, whether in an action of contract, negligence or other tortious action, arising out of or in connection with the use or performance of information available from this server.

The documents and related graphics published on this server could include technical inaccuracies or typographical errors. Changes are periodically added to the information herein. Mondaq Ltd and/or its respective suppliers may make improvements and/or changes in the product(s) and/or the program(s) described herein at any time.


Mondaq Ltd requires you to register and provide information that personally identifies you, including what sort of information you are interested in, for three primary purposes:

  • To allow you to personalize the Mondaq websites you are visiting.
  • To enable features such as password reminder, newsletter alerts, email a colleague, and linking from Mondaq (and its affiliate sites) to your website.
  • To produce demographic feedback for our information providers who provide information free for your use.

Mondaq (and its affiliate sites) do not sell or provide your details to third parties other than information providers. The reason we provide our information providers with this information is so that they can measure the response their articles are receiving and provide you with information about their products and services.

If you do not want us to provide your name and email address you may opt out by clicking here .

If you do not wish to receive any future announcements of products and services offered by Mondaq by clicking here .

Information Collection and Use

We require site users to register with Mondaq (and its affiliate sites) to view the free information on the site. We also collect information from our users at several different points on the websites: this is so that we can customise the sites according to individual usage, provide 'session-aware' functionality, and ensure that content is acquired and developed appropriately. This gives us an overall picture of our user profiles, which in turn shows to our Editorial Contributors the type of person they are reaching by posting articles on Mondaq (and its affiliate sites) – meaning more free content for registered users.

We are only able to provide the material on the Mondaq (and its affiliate sites) site free to site visitors because we can pass on information about the pages that users are viewing and the personal information users provide to us (e.g. email addresses) to reputable contributing firms such as law firms who author those pages. We do not sell or rent information to anyone else other than the authors of those pages, who may change from time to time. Should you wish us not to disclose your details to any of these parties, please tick the box above or tick the box marked "Opt out of Registration Information Disclosure" on the Your Profile page. We and our author organisations may only contact you via email or other means if you allow us to do so. Users can opt out of contact when they register on the site, or send an email to unsubscribe@mondaq.com with “no disclosure” in the subject heading

Mondaq News Alerts

In order to receive Mondaq News Alerts, users have to complete a separate registration form. This is a personalised service where users choose regions and topics of interest and we send it only to those users who have requested it. Users can stop receiving these Alerts by going to the Mondaq News Alerts page and deselecting all interest areas. In the same way users can amend their personal preferences to add or remove subject areas.


A cookie is a small text file written to a user’s hard drive that contains an identifying user number. The cookies do not contain any personal information about users. We use the cookie so users do not have to log in every time they use the service and the cookie will automatically expire if you do not visit the Mondaq website (or its affiliate sites) for 12 months. We also use the cookie to personalise a user's experience of the site (for example to show information specific to a user's region). As the Mondaq sites are fully personalised and cookies are essential to its core technology the site will function unpredictably with browsers that do not support cookies - or where cookies are disabled (in these circumstances we advise you to attempt to locate the information you require elsewhere on the web). However if you are concerned about the presence of a Mondaq cookie on your machine you can also choose to expire the cookie immediately (remove it) by selecting the 'Log Off' menu option as the last thing you do when you use the site.

Some of our business partners may use cookies on our site (for example, advertisers). However, we have no access to or control over these cookies and we are not aware of any at present that do so.

Log Files

We use IP addresses to analyse trends, administer the site, track movement, and gather broad demographic information for aggregate use. IP addresses are not linked to personally identifiable information.


This web site contains links to other sites. Please be aware that Mondaq (or its affiliate sites) are not responsible for the privacy practices of such other sites. We encourage our users to be aware when they leave our site and to read the privacy statements of these third party sites. This privacy statement applies solely to information collected by this Web site.

Surveys & Contests

From time-to-time our site requests information from users via surveys or contests. Participation in these surveys or contests is completely voluntary and the user therefore has a choice whether or not to disclose any information requested. Information requested may include contact information (such as name and delivery address), and demographic information (such as postcode, age level). Contact information will be used to notify the winners and award prizes. Survey information will be used for purposes of monitoring or improving the functionality of the site.


If a user elects to use our referral service for informing a friend about our site, we ask them for the friend’s name and email address. Mondaq stores this information and may contact the friend to invite them to register with Mondaq, but they will not be contacted more than once. The friend may contact Mondaq to request the removal of this information from our database.


This website takes every reasonable precaution to protect our users’ information. When users submit sensitive information via the website, your information is protected using firewalls and other security technology. If you have any questions about the security at our website, you can send an email to webmaster@mondaq.com.

Correcting/Updating Personal Information

If a user’s personally identifiable information changes (such as postcode), or if a user no longer desires our service, we will endeavour to provide a way to correct, update or remove that user’s personal data provided to us. This can usually be done at the “Your Profile” page or by sending an email to EditorialAdvisor@mondaq.com.

Notification of Changes

If we decide to change our Terms & Conditions or Privacy Policy, we will post those changes on our site so our users are always aware of what information we collect, how we use it, and under what circumstances, if any, we disclose it. If at any point we decide to use personally identifiable information in a manner different from that stated at the time it was collected, we will notify users by way of an email. Users will have a choice as to whether or not we use their information in this different manner. We will use information in accordance with the privacy policy under which the information was collected.

How to contact Mondaq

You can contact us with comments or queries at enquiries@mondaq.com.

If for some reason you believe Mondaq Ltd. has not adhered to these principles, please notify us by e-mail at problems@mondaq.com and we will use commercially reasonable efforts to determine and correct the problem promptly.