Internet: Does private browsing guarantee anonymity?

Private browsing prevents anyone else with access to your computer from seeing your online activities later . This is useful, for example, on a public or shared computer, so you don't leave behind any compromising login details or history.

However, it's important to understand that this privacy is primarily local (on your device). Private mode doesn't mean you're browsing anonymously on the internet itself. It's not a "shield of invisibility" from the websites you visit, your internet service provider (ISP), or your employer.

As indicated by the National Commission for Information Technology and Civil Liberties (CNIL) , even in private mode, sites can collect information via cookies (small files that record your preferences and online activities) or fingerprinting techniques , which allow a user to be uniquely identified by analyzing the technical characteristics of their browser.

Studies confirm the technical limitations of private mode . Traces remain even after closing the session, contradicting what the browser documentation claims. An analysis on Android revealed that RAM stores sensitive data : keywords, identifiers, cookies, recoverable even after reboot.

Private mode does not block advertising cookies; it simply deletes them at the end of the session. When you return to a site in a new private session, it does not "remember" previous choices: you therefore often have to redefine your preferences (accept or refuse cookies). Cookie consent banners, well known to European Internet users since the entry into force of the General Data Protection Regulation (GDPR) and the ePrivacy directive, therefore systematically reappear. Consent fatigue pushes many Internet users to accept everything without reading .

In France, 65% of Internet users systematically accept cookies , despite better information on the subject in recent years. However, Internet users are aware of the risks associated with their online privacy, but do not systematically act , often due to a lack of knowledge or confidence in the available tools. Some sites even hide the "Refuse" option to influence you: a well-designed panel can reduce acceptances by half .

Private mode alone isn't enough to guarantee online anonymity. To better protect your privacy, you need to combine several tools.

A VPN (virtual private network ) creates a secure tunnel between your device and the internet, allowing you to browse more privately by encrypting your data and masking your IP address. In 2024, 19% of French VPN users primarily want to hide their activity, and 15% want to protect their communications .

A browser like Tor goes further: it bounces your requests through multiple relays to completely mask your identity. It's a favorite tool of journalists and activists, but its slowness can discourage everyday use. Alternatives like Brave or Firefox Focus offer enhanced anti-tracker modes, while extensions like uBlock Origin or Privacy Badger effectively block ads and trackers. These extensions are compatible with major browsers like Chrome, Firefox, Edge, Opera, and Brave.

It's also essential to adopt digital hygiene: manage cookies, limit permissions, prefer search engines like DuckDuckGo, which don't store your searches, don't profile you, and automatically block many trackers, and avoid centralizing your data in a single account. Online, true privacy relies on a comprehensive, proactive, and informed approach.