How anonymous are you online? And how to become more so
Anonymity is not a switch, it is a scale. Most people think incognito mode solves it — but that mainly removes the traces on your own machine, not towards the world.
Let us start with the most important clarification: an incognito window does not make you anonymous. It does what it promises — it saves no history, cookies or filled-in form data on your own machine. That is useful if you share a computer. The site you visit, your internet provider and your workplace network, however, still see everything.
Let us go through what actually identifies you, from the most common to the least known.
1. The IP address
This is the best-known identifier. Every internet connection has an address, which the site you visit can see. From it, the approximate geographic location (at city level) and your internet provider are typically revealed.
On its own it usually does not identify a person — a home address generally belongs to the household, and with many providers it changes from time to time. The internet provider, however, knows exactly which subscriber a given address belonged to at a given moment.
What can be done? A VPN or the Tor browser. A VPN hides your traffic from your provider, but opens it up towards the VPN provider — that is, you relocate trust rather than eliminate it. A free VPN is particularly not worth using: their business model is often precisely the sale of your data.
2. Browser fingerprinting
This is the one fewest people know about, and the hardest to defend against.
Every browser gives away small details about itself: the screen resolution, the time zone, the language setting, the installed fonts, the characteristics of the graphics card, the supported features. None of them identifies you on its own — but the combination is often unique.
This technique is unpleasant because it requires no cookies. You can delete cookies, you can be in incognito mode: the fingerprint stays the same.
What can be done? It is hard to prevent entirely. What helps:
- Using a browser that deliberately standardises the fingerprint (the Tor browser does this: it tries to make everyone look alike).
- Anti-tracking extensions — but note, an unusual combination of extensions itself makes you unique. Less is sometimes more.
- Turning on the browser's built-in tracking protection.
3. Logged-in accounts
The simplest and most underestimated form of identification: if you are logged in somewhere, then they know who you are. Fingerprinting and IP addresses are secondary to that.
If you are logged in to your main account in the same browser, and you view another site in the same place, then the two activities are tied to the same browser profile.
What can be done? This is the step with the best return on effort: use a separate browser profile — or a separate browser altogether — for what you want to keep apart. It requires no expertise, takes five minutes to set up, and eliminates most of the linking.
4. Metadata
It is not only what you say that counts, but also when, to whom and how often.
This is true of encrypted communication too: the content stays hidden, but it is generally visible that two parties are in contact. For an analyst the pattern is often more telling than the text.
This includes the hidden data in photos. A picture taken with a phone often contains the exact GPS coordinates and a timestamp. If someone forwards such a picture directly, they send their location with it.
What can be done? Before sending a photo, take a screenshot of it — that contains no original location data. It is the simplest method, and it needs no tools at all.
5. What you write about yourself
In most cases it is not some sophisticated technique that gives a person away, but what they share voluntarily.
Individually innocent pieces of data: which district you live in, what job you do, how old your dog is, when you went on holiday and where. From four or five such details a motivated person can assemble an identity — and these days that takes no special tools at all.
There is no technical protection against this. Only attention.
Realistic goals, by effort
Anonymity has a price in convenience. It is worth deciding what you are protecting yourself against, and choosing accordingly.
If the goal is that an acquaintance or your workplace does not stumble across you — this is the most common case, and relatively simple:
- a separate email address
- a username and photos used nowhere else
- a separate browser profile
- your main social accounts logged out in that profile
This package covers most everyday situations, and it costs nothing.
If the goal is that not even a determined individual can identify you — that already takes a VPN, strict browser settings and consistent discipline about what you write about yourself.
If the goal is to defend against state-level surveillance — that is a different genre, and this article is not enough for it. There, Tor, strictly separated devices and serious professional material are the starting point.
One thing not to forget
Anonymity is not retroactive. What you have once revealed about yourself cannot be taken back: it may have been saved, copied or photographed.
That is why it pays to set up the few basics at the start, rather than trying to repair things afterwards. The first step is the cheapest.