The word "cookie" is plastered across warning banners all over the web today. Yet, its technical nature often remains misunderstood. A cookie is neither a virus nor a computer program capable of infecting a device. It is simply a small, passive text file that your web browser (Chrome, Safari, Firefox) stores on your hard drive at the request of a website.
To understand the current internet privacy landscape, we must first understand what this file was originally designed for, and how its use has been diverted.
1. The cloakroom analogy: The original purpose of the cookie
Imagine going to a public swimming pool. At the entrance, you leave your belongings at the cloakroom, and the attendant hands you a wristband with a number. This wristband does not contain your name or your address. It serves one purpose: when you return, the attendant looks at the number and knows exactly which basket belongs to you.
The web operates in the exact same way. By default, the internet has "amnesia." When you navigate from one page to another on the same site, the server forgets who you are.
This is where the original cookie (known as a "first-party cookie") comes in. When you log in or add an item to your shopping cart, the site gives you a small text file containing a unique identifier (your cloakroom number). With every new page loaded, your browser shows this file to the site, which "remembers" you. Without these technical cookies, modern e-commerce or logged-in user areas simply would not exist.
2. The drift: When the cloakroom number follows you down the street
The issue arises with the introduction of "third-party cookies."
Returning to the analogy: imagine now that the company manufacturing the pool's wristbands also supplies the local library, the supermarket, and your neighborhood bakery. Every time you enter one of these places, the same company reads your number.
On the web, these companies are advertising networks or external analytics tools. A news website embeds a social media button or a third-party tracking script. This tool places its own cookie on your computer. When you later visit a travel booking site using the same tool, your file is read again.
The goal is no longer to remember your shopping cart, but to connect your visits across the web to deduce your habits, your interests, and build a behavioral profile.
3. What these files actually contain
A tracking or advertising cookie does not usually contain your explicit name. Most often, it contains:
- A long, complex unique identifier (e.g.,
id=7a9b2c4e-8f1d...). - An expiration date (ranging from a few days to several years).
- The domain name of the company that created it.
- Sometimes, encoded data regarding your previous interactions with the brand.
While this data appears anonymous, cross-referencing hundreds of unique identifiers across thousands of websites allows companies to indirectly identify an individual with high precision.
4. When the tool becomes a vulnerability: Real cases of fraud and abuse
The very nature of cookies—locally stored text files used to authenticate or profile a user—has led to major abuses, recognized both legally and technically. These drifts fall into two categories: security breaches and privacy violations.
Cookie theft and forgery (The Yahoo case, 2013-2016) If a cookie acts as a passport proving a user is logged in, stealing it is equivalent to stealing their digital identity without needing their password. Between 2013 and 2016, Yahoo suffered one of the largest attacks in internet history. Hackers gained access to the company's source code and learned how to generate (forge) Yahoo's authentication cookies. As a result, they fraudulently accessed over 32 million user accounts simply by inserting these fake cookies into their browsers. This event undeniably proved the massive security risk of storing access authorizations in simple text files.
Sanctioned abusive tracking (The Criteo case, 2023) On the privacy front, the fraudulent use of tracking cookies has been firmly punished by authorities. In June 2023, the CNIL (the French Data Protection Authority) fined the French advertising targeting company Criteo 40 million euros. The investigation proved that the company was placing tracking cookies on users' devices without ensuring they had given valid consent. The profiles created from these cookies contained browsing histories so vast that they constituted a clear violation of the GDPR (General Data Protection Regulation).
5. The alternative: Analytics via the ephemeral footprint
Faced with these security and privacy risks, the audience measurement model had to evolve. It is entirely legitimate for a website creator to want to know their page traffic, but it is no longer justifiable to do so at the expense of their visitors' data.
This is where the Alternytics approach comes in: cookieless analytics.
Instead of dropping a persistent file on your hard drive, the method relies on an ephemeral footprint. When a page loads, the system registers a simple, anonymized request (a "ping"). There are no stored behavioral profiles, no cross-referencing of data between different websites, and no technical possibility of identifying the user after their session ends.
The result is absolute respect for privacy: the website owner gets the necessary metrics (page views, reading time) to improve their content, and the user retains full control over their browser, without ever being tracked.
Technology today allows us to measure performance without compromising confidentiality. It is simply a matter of choosing the right tools.