Companies are profiling you from your smartphone use – how to stop them

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• Marketing and advertising agencies want your data.
• Organizations want to know your location, how you shop, and more.
• Explore our guide to preserve your right to privacy.

Companies often have access to more data about you than you realize — and many records used to profile you won't require your outright, knowing consent. 

Whenever you browse a website, submit a search query, accept a cookie notice, make a purchase, post on social media, or even visit a location, your activity may be recorded. Now, a singular visit to a website doesn't tell a marketer much about you, your interests, or what you might be interested in buying — but over time and multiple interactions, a detailed picture of you forms. 

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Your personal details, location, purchase history, income bracket, interests, and more may all be recorded and linked to your IP address, email, or social media presence. 

These profiles, which may also be shared, sold, or traded between marketing agencies and other third parties, allow organizations to perform targeted advertising — and use every psychological trick in the book to lure you to make a purchase.

While it can be difficult to keep your information out of the hands of agencies and brokers, below, you will find a breakdown of the most common ways you are being profiled online and how you can reduce the flow of your data.

Why do companies want my information, and what do they do with it?

Data is now currency. Your information and attention are huge revenue drivers for companies that provide services ranging from analytics and consumer technology to marketing and hospitality.

With enough data, organizations can create detailed reports on individual consumers — known as shadow profiles — and each signal can be exploited for targeted advertising, tailored communication, and to customize campaigns to lead you to purchase decisions, or to visit affiliates and partners online. 

Our smartphones are now hubs of activity. We use them to surf the internet, make purchases, communicate with others on social media, consult maps, and log our health and fitness data — the list goes on. With each data point (or "signal"), companies can learn about our whereabouts, our habits, our interests, who we talk to, and what we like to buy.

Information that companies may collect about you from your smartphone includes:

• Your name
• Personally Identifiable Information (PII), including home location, age, and date of birth
• Smartphone device identifiers: language, operating system, model, IP address, MAC address
• Contact information, such as your phone number or email address
• Public social media records, engagements, and posts
• Data synced with your vehicle, such as contact information, messages, entertainment preferences, and GPS logs
• Shared health and fitness logs
• Place of work, likely salary range, and education level
• Interests, hobbies, and search queries
• Mobile app usage telemetry and records

Shadow profiles are all about patterns, not individual data points, which can be aggregated to create an accurate portrait of you. The range of data collected depends on the mobile and online services you use, their terms and conditions — including data-sharing agreements — and what you post publicly online. 

1. Browser activity

Unless you are using a secure mobile browser, this gateway to online services is a goldmine for consumer data collection. 

Take this example. You need a new outfit for a wedding you are attending. You type your search query into Google on your smartphone for a formal event clothing store, together with the name of your city — as you might want to try something on before purchase. You choose the search term "luxury" over "budget." You then visit several local companies' websites.

You have now revealed your device identifier, a search term, an area, and a product you're interested in. What you browse could help organizations pinpoint your taste in clothing, as well as your potential budget, estimated or probable income level, and how far you're willing to travel. 

Our search queries, interests, location, websites we visit, browsing habits, and more can all be revealed in a simple online query. Stitched together with our smartphone's device identifiers, a profile is already on its way to being built. 

2. Online purchases

If you decide to buy online instead, additional signals can be captured either via your mobile browser or by downloading and installing a store's dedicated app. 

How long you linger on a product page, your purchase decisions, whether or not you use discount offers and promotions, and how you engage with a website or app can all reveal a lot about you. In turn, this profile can be used to tailor marketing campaigns or loyalty programs based on your demographic data, purchase history, and interests. 

Over time, the same information may be used to predict your future spending. 

3. Social media engagement

Now you've made your purchase. You take a photo of yourself with your smartphone's camera, post it publicly on Instagram, and tag the store. You leave a glowing review and tag a few friends who are going to the same event and might be interested in buying their own outfits from the same place. 

This single post has now revealed your purchase, potentially your location, your contacts and their links to you and the social event, how you are likely to engage with other stores, your physical appearance, age range, and social media usage.

If you engage with other social media pages and profiles, this, too, can be collected by organizations for profiling purposes. This may include the types of business you are connected to, where you post, what you like, and how often you view certain profiles and for how long. All of this data is usually collected by social media platforms for advertising purposes and may be shared with third parties, depending on their terms and conditions. 

4. Mobile apps

The mobile applications you use, how often you use them, and what types of software you prefer can all be shared by developers with other organizations. For example, a stocks-and-shares app could create a signal that you have financial interests, which could be used to sell you financial services. 

Or, the use of a dating app could lead to targeted adverts for singles appearing in your email inbox. 

Developers may also use the same signal to measure app engagement and improve app features — but, in turn, this could be exploited for in-app partnership sales opportunities. 

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There's also the problem of your advertising ID, buried in your settings, that links your device to you and could be used for targeted advertising. 

"The biggest risk is aggregation," Yasir Zahid, head of business security at Secure.com told ZDNET. "Advertising IDs act as a persistent identifier that links your activity across apps and ad-tech SDKs even when no single app knows your full picture. A weather app, shopping app, fitness app, or travel app may each collect a small piece of context, but together — tied by that common identifier and shared with data brokers — those pieces become a behavioral profile: where you go, what you are interested in, what routines you follow, and even which sensitive places you visit. Most users rarely have full visibility into how often this data is collected, how long it is stored, or who it is shared with."

5. Subscription services

If you access a subscription service on your mobile device, this can also reveal more data to add to your shadow profile. Regardless of whether you use Netflix mainly on your smart TV and only occasionally on your smartphone, data points can still be collected and linked to your profile.

Your streaming service app usage, device identifiers, viewing habits, preferred genres and interests, general location, personal account details, what you've searched for, and how you engage with the service are all potentially up for grabs.

How companies connect the dots between you, your devices, and online services

Companies don't need to know your name to create a shadow profile of you. You don't even need to use a specific online service.

Your smartphone's ID, Wi-Fi, or cellular connection, GPS, or even Bluetooth can all generate signals that are connected to your shadow profile. Combine this with device and browser fingerprinting — the collection of device-related data — and the foundations for a concrete profile are in place. 

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Next, we add cross-service tracking technologies, including the email address you use to sign up for online services and apps, cookies, advertising IDs, and behavioral patterns such as browser and search activity, purchases, website and app engagement, interests, and social media activity, and you have a profile that may be far more detailed than you'd imagine. 

These profiles may be further bolstered when companies purchase consumer data from data brokers. Sensitive information, PII, and more can be legally stored, shared, and purchased by these firms, which then sell it on to other companies without your knowledge or consent. 

How to stop being profiled through your smartphone

While our guide focuses on the data flowing between your smartphone and third parties, you can also apply the advice below to any Internet-connected device you own, such as a laptop or PC.

• Audit your app and smartphone permissions: An often overlooked area that drastically impacts our privacy — and the data collected about us — is app permissions. To stop your handset from leaking signals and data that could be aggregated for profiling purposes, check out our guide on performing a permissions audit on your smartphone. 
• Turn off personalized advertisements: Go to the settings or options for any online service, account, or app you use and ensure that personalized advertising is turned off. This is especially important on social media, as data may be pulled from your shadow profile for targeted product placement and advertising. 
• Delete or turn off your advertising ID: Your advertising ID links your mobile device to marketers and other organizations, allowing them to potentially identify you and serve tailored ads through websites and search results. On Android, you will find this option under the Ads tab in Privacy & Settings (use the search bar if it is hidden). On iOS, you will find this option in Privacy & Security > Tracking.
• Use a secure browser app: A secure browser will not store or sell your information and should not collect any search queries or browsing history. Using a secure browser app on your smartphone will reduce the risk of being profiled, and we recommend browsers for this purpose, including Brave and the Tor Browser. 
• Install a private search engine app: If you don't want to change your browser, you can at least reduce your online footprint by using a private search engine. DuckDuckGo is our favorite. 
• Say no to cookies and opt out: Whenever possible, reject any additional cookie notices on websites and stick with "essential cookies only" required for website functionality. Furthermore, opt out of any personalized adverts and tracking requests.
• Install a VPN: Using a Virtual Private Network (VPN) service is a great way to disguise your online activity and mask your IP address — and the best providers out there all offer Android and iOS apps. Not only can a VPN protect your data and privacy, but it can also help you avoid geolocation blocks and encrypt your online communication, keeping it out of eavesdroppers' hands. 
• Create a junk email address: Creating a second email address can keep clutter out of your main inbox, as well as break connections between you and your true email address. Whenever you make a purchase online or sign up for a service you only intend to use casually, use your junk address instead. 
• Delete and remove unused services and apps: This is good practice for your security and privacy, overall, but it can also help reduce the data flow between your device and third-party organizations. If you're not using an app or online service anymore, delete the accounts associated with it. An app doesn't have to be actively used to retain permissions and transmit your information.
• Use a data removal service: If you want to keep your information out of data brokers' hands, consider signing up for a dedicated service to do so for you. The issue with data brokers is that one data deletion request is never enough — as your information is repeatedly acquired from different sources, you have to be persistent in asking for removal. One of our favorite data removal services can shoulder this task for you.