Canada: Ultrasonic, Cross-Device Tracking Is Here, Beware

Last Updated: December 16 2015
Article by Lisa R. Lifshitz

Worried about the use of tracking cookies that follow you around the Web and serve you targeted ads? No need to fret anymore since those cookies are now so passé! There is now something new to keep you up at night: cross-device tracking.

Cross-device tracking allows marketing companies to surreptitiously follow your online behaviour over various devices (including phones, tablets, televisions and computers) through the use of inaudible, high-frequency sounds. Users are generally unaware of it and the kinds of data being collected about them through this process.

Concerns relating to this issue are gaining traction south of the border. In its an October letter/submission to the United States Federal Trade Commission, the Center for Democracy & Technology, a digital human rights and privacy organization, said at the high level, cross-device tracking works by determining which user is using a device, assigning the user/device a unique identifier, and then storing these identifiers in a table.

As individuals often use several devices during a day (phones, computers, tablets, wearable health device, RFID fobs, etc.), marketers can combine all their data streams by linking them to the same individuals, enhancing the granularity of what they know about the person, and creating detailed profiles of individual users. Thus identifying recognition of long-term behavioural/shopping patterns.

Advertisers generally employ cross-device tracking in two ways.

"Deterministic tracking" occurs when users log into their online accounts. The owner then tracks and records their actions and if the user is signed into the platform on different devices, the company can track him or her across devices. The value of this data is limited since it is only available to the platform owners themselves (and any other third parties that they sell or otherwise provide the information to).

Without logins, marketers can use "probabilistic tracking," which relies on aggregated information from multiple devices, including IP addresses, device type, web browser, and other setting to create digital fingerprints that links one individuals across devices.

Marketers can also determine user's identities through "browser fingerprinting": making inferences through users' browser customizations, in addition to tracking their web movements, to (eventually) create a unique signal that web sites can use to uniquely identify the user (and which is virtually impossible to opt out of).

However, the most interesting/scary cross-device tracking method reported by the CDT is the use of inaudible ultrasonic sound beacons, led by a company called SilverPush.

When a user encounters a SilverPush advertiser on the Internet, the advertiser drops a cookie on the user's computer while playing an ultrasonic audio through the device's speakers. The other smart device recognizes the inaudible code because of the software development kit installed on it.

SilverPush technology can also embed audio beacon signals into television commercials that are silently picked up by an app installed on the user's device, completely unknown to the user. The audio beacon allows a tracker to know which ads the user saw, how long the user watched the ad before changing the channel, which kind of smart devices the individual uses, along with other information that adds to the profile of each user linked across the various devices.

The device owner/user is oblivious to the beacon, but if the device has a SilverPush-based app on it, once the beacon is detected, the device is recognized as being used by the same individual (you). So as the Atlantic recently quipped, your phone is literally listening to your TV, all in the name of serving you more targeted ads. Yikes!

Currently, there is no way to opt out of this kind of cross-device tracking and only distance hinders the receipt of an audio beacon. The CDT's letter noted that as of April 2015, SilverPush's software was being used by six or seven apps and the company monitored 18 million smartphones.

Not surprising, this level of detailed surveillance and tracking has raised considerable privacy concerns, not the least that some companies will be able to combine information from different devices to create highly intrusive profiles of persons that may or may not even be accurate.

In response to growing concerns and to get more input, the FTC held a workshop Nov. 16 as first step to examine the privacy issues around these types of tracking and marketing activities.

While the FTC did not issue any formal guidance as a result, chairwoman Edith Ramirez emphasized that regardless of the technology, companies should continue working to address issues of transparency, notice, and choice in this area.

She also highlighted the self-regulatory efforts of the advertising industry on cross-device tracking, including the Digital Advertising Alliance and the Network Advertising Initiative.

Maneesha Mithal, the associate director of the FTC's division of privacy and identity protection, identified the five key takeaways from the workshop:

(1) the benefits of cross-device tracking, including maintaining state, frequency capping, and seamless user experiences across devices;
(2) the need to provide greater transparency, choices, and education for consumers;
(3) the need to consider the consumer experience;
(4) that there is room for industry innovation in this space; and
(5) that companies should be mindful of their representations in this space and adhere to those representations.

The public comment period for the workshop is open until Dec. 16.

Interestingly, on the same the day the FTC held this workshop, the DAA, a powerful industry group whose policies are often contractually adopted by advertisers, ad agencies, ad networks, and publishers, released a guidance document entitled "Application of the Self-Regulatory Principles of Transparency and Control to Data Used Across Devices," confirming its existing principles for tracking online behaviour and and other new tech standards apply to multi-site and cross-app data collection.

Marketers that collect cross-device data must include notices on their web sites that that data collected from a particular browser or device may be used with another computer or device linked to the browser or device on which such data was collected, or transferred to a non-affiliate for such purposes. Additionally, marketers must provide a device-specific consumer opt-out.

It's fair to say in Canada our privacy regulators would likely not be impressed with the surreptitious nature of current cross-device tracking practices. The federal Office of the Privacy Commissioner of Canada recently reiterated and confirmed its position in the "Online Behavioural Advertising (OBA) Follow Up Research Project" published in June 2015.

In 2011, the OPC issued guidelines to help various organizations involved in OBA to ensure that their practices are fair, transparent, and in accordance with PIPEDA. One of the foundations of the guidelines is that OBA involves the collection of highly personal and personalized information.

The guidelines stated that opt-out consent for OBA could be considered reasonable under PIPEDA provided it is carried out under certain parameters:

(i) Individuals are made aware of the purposes for the practice in a manner that is clear and understandable – the purposes must be made obvious and cannot be buried in a privacy policy. Organizations should be transparent about their practices and consider how to effectively inform individuals of their online behavioural advertising practices, by using a variety of communication methods, such as online banners, layered approaches, and interactive tools;
(2) Individuals are informed of these purposes at or before the time of collection and provided with information about the various parties involved in online behavioural advertising;
(3) Individuals are able to easily opt-out of the practice - ideally at or before the time the information is collected;
(4) The opt-out takes effect immediately and is persistent;
(5) The information collected and used is limited, to the extent practicable, to non-sensitive information (avoiding sensitive information such as medical or health information); and
(6) Information collected and used is destroyed as soon as possible or effectively de-identified.

In addition, the OPC stipulated two restrictions:

(i) Any collection or use of an individual's web browsing activity must be done with that person's knowledge and consent. Therefore, if an individual is not able to decline the tracking and targeting using an opt-out mechanism because there is no viable possibility for them to exert control over the technology used, or if doing so renders a service unusable, then organizations should not be employing that type of technology for online behavioural advertising purposes.
(2) As PIPEDA requires meaningful consent for the collection, use and disclosure of personal information, it is difficult to ensure meaningful consent from children to online behavioural advertising practices. Therefore, as a best practice, organizations should avoid tracking children and tracking on websites aimed at children.

If these conditions and restrictions are not met, and an organization wishes to continue to use OBA, then explicit consent is required.

The OPC also noted in its Guidelines on Privacy and Behavioural Advertising that any collection or use of an individual's web browsing activity must be done with that person's knowledge and consent and "If an individual is not able to decline the tracking and targeting using an opt-out mechanism because there is no viable possibility for them to exert control over the technology used, or if doing so renders a service unusable, then organizations should not be employing that type of technology for online behavioural advertising purposes."

It is not clear how many Canadian companies are currently using cross-device tracking, but they will be expected to comply with existing Canadian privacy requirements relating to transparency and opt-out capability.

However, it is difficult to see how the use of inaudible ultrasonic audio beacon signal tracking technology will easily allow individuals to "exert control over the technology used" from a practical perspective or how to avoid tracking children while using this technology.

I will continue to report on developments in this area as they arise.

On a personal note, I wish all of my faithful readers happy holidays and a healthy New Year!

Originally published by Canadian Lawyer Online - IT Girl Column

The content of this article is intended to provide a general guide to the subject matter. Specialist advice should be sought about your specific circumstances.

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

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

Lisa R. Lifshitz
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 (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

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’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 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

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

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

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