Once you typed in “running shoes” in a search bar, and for the next two weeks, all websites that you visit seem to know about it. Someone mentioned a vacation in Portugal near your smartphone, and suddenly all of your feeds are filled with flight offers. It looks like a coincidence until it occurs for the second, third, and tenth time – and then everything begins to look very different.
The truth is not as mysterious as it seems, but probably more complicated than most people imagine. It is not a single omniscient system watching you everywhere; you are being tracked by a dozen different systems, each of which collects its own piece of information about your activity. All these pieces of information are joined together into a portrait of you, which is usually more detailed than what your closest friends know about you.
Here is how all this happens.
The Trail You Leave Without Even Trying
Every time you open a website, your browser gives much more information than most of us expect. It is not only about the things that you have typed and clicked on. It is also about the type of your device, screen resolution, fonts that you have installed, time zone, battery level, and dozens of other details that, combined together, form something called a browser fingerprint.
No individual item from this list identifies you as a single person; combined together, however, these technical details usually become unique enough to distinguish you among millions of other internet users.
Cookies also play a part, although a more complicated one. Safari and Firefox do not use third-party cookies anymore, which eliminates a great deal of cross-site tracking on these browsers. Chrome still holds the largest share of internet traffic, and instead of implementing its plan to stop using cookies entirely, it decided to let users choose their preferences concerning cookies in the settings.
Practically, this means that a vast majority of users are tracked across different websites without their knowledge, simply because of their default settings.
Furthermore, many modern websites embed dozens of small tracking scripts created by ad networks, analytics companies, and social media platforms. A simple news article contains dozens of such scripts that quietly report your visit to their parent companies.
Search engines also collect a large amount of information about you. Each of your searches is accompanied by information about your approximate location, the device you are using, and the search results you have finally clicked on.
Over a period of weeks and months, your search history turns into a surprisingly detailed and accurate map of your fears, hopes, worries, and plans, and therefore becomes very valuable for advertisers.
Your Smartphone Also Spies on You
If your browser is one window into your activity on the internet, your smartphone is a much larger one.
Apps ask your permission to access your location, contacts, microphone, photos, and even your camera. Usually, this is done for no obvious reason; for example, flashlight apps do not need to know your location to perform their functions, and a game does not need your contact information either.
Yet both types of apps ask to access this data, and users usually give them permission just to get rid of additional clicks.
Location data is very revealing. It allows companies to learn where you live and work, which doctor you visit, and where you spend your time. Combined with patterns in your app usage, it forms a fairly complete portrait of your everyday activity without you ever typing a word into a search engine.
Two facts about the flow of this information are worth noting:
- Many free apps make their money by selling anonymized or aggregated user data, not by placing ads.
- Location and behavioral data collected by an app are shared with advertising partners through software development kits embedded in the app.
The Middlemen You Have Never Heard About
Behind all these activities works a rather unknown industry that collects, buys, connects, and sells all kinds of information about you, including your browsing and app history.
A data broker knows all kinds of information about you, such as your approximate income, marital status, shopping habits, political preferences, and health interests. All this information is collected from dozens of sources, and you never gave any agreement to most of these brokers.
Moreover, there is no easy way to find out what kind of profile they have created about you.
The thing that makes it so hard to keep track of is how deep this industry goes. Broker #1 sells raw data to broker #2, who combines it with data from another source and resells it to broker #3, who repackages it under another name.
Thus, by the time your data reaches the advertiser or background check company, it has passed through several levels and has gained some new details that are practically impossible to trace.
How the Pieces of Information Become Connected
It would not matter much if all of these separate sources remained separate. The true power comes from connecting all these pieces of information about you together.
Advertisers use device IDs, email hashes, and login credentials to join all of your activity on different apps and browsers into one portrait.
If you are logged into the same account on your smartphone and your laptop, an advertiser can connect all your activity across these devices and create a single portrait, even though you did not do it yourself.
This is how an advertisement for something that you searched for on your work laptop appears on your smartphone. It is not magic, and it is not your microphone listening to your speech, despite popular myths.
This is identity resolution, a process that is specifically designed to merge fragmented information into one portrait of a person.
Why It Really Matters
It is easy to ignore this whole problem as the price of using free services, and many people do exactly that. However, there are much more serious consequences than just creepy advertisements.
Detailed profiles can influence insurance prices, travel prices, loan conditions, and even job offers. Data breaches at brokers or advertising companies can expose sensitive information, including health conditions or financial history, to people who should not have access to it.
There is also the issue of the permanence of this information. Data collected today can stay in a database for years, regardless of the circumstances in which it was collected.
A search that you performed during a difficult period of your life or a single location that you visited can stay in your profile forever and influence decisions that are made about you in the future.
What You Can Do to Protect Yourself
You cannot avoid participating in this economy of data collection, but you can limit the amount of information that is collected about you.
Some practical advice that really works:
- Periodically check application permissions on your smartphone and revoke access to location, contacts, or microphone if it is unnecessary.
- Use your browser’s privacy settings or simply switch to a browser that blocks fingerprinting by default.
In addition to this, use a VPN service when you work with public Wi-Fi or even while browsing the internet. It protects you from certain types of tracking by encrypting your traffic and changing your IP address, so networks and trackers have fewer chances to recognize you.
Of course, cookies and app-based trackers will continue working independently from your network connection, but combined with careful permission settings and a privacy-focused browser choice, a VPN service closes one more path of tracking used by advertisers and data brokers.
It is also worth checking what brokers have already collected about you. Today, several services allow you to search your name across broker databases and request the removal of your data from them.
Usually, this process takes a long time and must be repeated periodically because new brokers continue appearing.
The Larger Picture
All this does not mean that you should disconnect yourself from the internet entirely and distrust every app.
Almost all of this happens simply because it is profitable, but nobody has any sinister intentions toward you personally.
Understanding how all these processes work, from browser fingerprints to smartphone permissions to data broker profiles, gives you a real choice in how much information you reveal about yourself unconsciously.
The internet knows so much about you not because it is so clever, but because thousands of mundane details are collected, connected, and sold every day.
Now that you understand it, the small changes you make from here are entirely up to you.
