https://coveryourtracks.eff.org/learn

When you visit a website, your browser makes a "request" for that site.
In the background, advertising code and invisible trackers on that site
might also cause your browser to make dozens or even hundreds of
requests to other hidden third parties. Each request contains several
pieces of information about your browser and about you, from your time
zone to your browser settings to what versions of software you have
installed.

Some of this information is passed along by default simply to help you
view the page. For example, HTTP headers are essential to most web
functionality, and broadcast your device and browser version. But a lot
of the information in your browser�s requests is also extracted by
third-party ad networks, which have sneaky tracking mechanisms embedded
across the Internet to gather your information.

At first glance, the data points that third-party trackers collect may
seem relatively mundane and disparate. But when compiled together, they
can reveal a detailed behavioral profile of your online activity, from
political affiliation to education level to income bracket. As long as
this trove of data about you is linked back to you, your online
activity can be logged. Ad networks primarily rely on two methods to
maintain this link: cookie tracking, and browser fingerprinting.
What are cookies?

Cookies are small chunks of information that websites store in your
browser. Their main use is to remember helpful things like your account
login info, or what items were in your online shopping cart�in other
words, they save your place. But they can also be misused to link all
your visits, searches, and other activities on a site together. This
use of cookies is a privacy violation, and browsers generally allow you
to block, limit, or delete cookies.
What is a digital fingerprint?

A digital fingerprint is essentially a list of characteristics that are
unique to a single user, their browser, and their particular hardware
setup. This includes information the browser needs to send to access
websites, like the location of the website the user is requesting. But
it also includes a host of seemingly insignificant data (like screen
resolution and installed fonts) gathered by tracking scripts. Tracking
sites can stitch all the small pieces together to form a unique
picture, or "fingerprint," of your device.
What is the difference?

Think of the small tracking devices scientists use to follow animal
migration patterns, or a GPS transmitter attached to a car. As long as
they�re attached to the target animal or vehicle, they are accurate and
effective�but they lose all value if they�re knocked off or discarded.
This is roughly how cookies behave: they track users up until the point
a user deletes them.

Fingerprinting uses more permanent identifiers such as hardware
specifications and browser settings. This is equivalent to tracking a
bird by its song or feather markings, or a car by its license plate,
make, model, and color. In other words, metrics that are harder to
change and impossible to delete.
Can I do anything about this?!

Completely blocking trackers is difficult, even with a fully-featured
tracker blocker. Even so, we recommend using the tracking protections
above. Privacy protection does not have to be perfect to make a big
difference!

There are two main dynamics that make trackers hard to entirely avoid
online:

Impact on Usability: It�s unfortunate that enhanced privacy often
comes at the expense of functionality. For instance, you may want to
disable JavaScript to stop tracking scripts from running. But this will
likely make it hard to shop, fill out forms, watch videos, or see
interactive web elements. Many pages require disabling your ad blocker
to see content, or refuse to load anything unless you use the
�official� app.

Identifiable Protections: Paradoxically, sometimes your protections
themselves can become part of your fingerprint. An add-on intended to
protect you can even lead to your full identification. Changing your
settings and installing protections can lead trackers to be identified.
In this case, you become a �mystery user with a very specific
combination of privacy protections installed.�

In practice, the most realistic protection currently available is the
Tor Browser, which has put a lot of effort into reducing browser
fingerprintability. For day-to-day use, the best options are to run
tools like Privacy Badger or Disconnect that will block some (but
unfortunately not all) of the domains that try to perform
fingerprinting, and/or to use a tool like NoScript( for Firefox), which
greatly reduces the amount of data available to fingerprinters.

Cover Your Tracks� primary goal is to help you determine your own
balance between privacy and convenience. By giving you a summary of
your overall protection and a list of characteristics that make up your
digital fingerprint, you can see exactly how your browser appears to
trackers, and how implementing different protection methods changes
this visibility. The following suggestions are simple, straightforward
protection methods, and are an excellent starting point.

Install a tracker blocker and watch your browsing experience get a lot
more pleasant

Most tracker blockers cross-reference massive lists of tracking
scripts. They then block any attempts to load an ad or other item that
matches.

When you block trackers, you prevent tracking companies from reading
your browser fingerprint. However, more advanced tracking techniques
may still be able to gather information about you.

Disabling Javascript

Most trackers run on JavaScript, and they can�t gather much of the
information used to determine your browser fingerprint without it.
Thus, your browser looks a lot less distinct, and is more protected.

But there is a trade off. Disabling JavaScript breaks a staggering
amount of websites, and limits the functionality of many more.
Changing browser settings from defaults

Tracking is so pervasive that all of the major browsers (Chrome,
Firefox, and Safari) come with settings that disable certain types of
tracking. Turning them on or off is as simple as going into the
settings menu and clicking a button.

Disabling tracking scripts in your browser settings is reliably
effective, though not as robust as a designated tracker-blocker.

For more info about what settings and protections your browser offers
compared to others, check out this article from Blacklight.
Using a fingerprint resistant browser

Some newer browsers were built to thwart fingerprinting, such as Tor
Browser and Brave. How they do this varies from browser to browser, but
they generally work by making your fingerprint less unique and/or less
consistent. This means trackers have a harder time following your usage
of the web.
Can my attempts to protect myself backfire? How can attempting to make
myself more anonymous actually make me more identifiable?

Each browser metric is highly connected to other metrics in complex
ways. This is why we don�t recommend trying to change a single element
of your fingerprint. Striving to get the most common result for any
individual metric may seem like a good idea, but it can actually make
your browser more identifiable.

Let�s look at an example of how these metrics are interconnected:

No matter what browser you�re using, they all send information about
themselves to servers so that web content loads correctly. This
information includes the browser name and version. If you swap out the
identifier of the browser you're actually using with one from a more
common browser, you may make yourself completely identifiable. How is
this possible? If Chrome is a more common browser, how can identifying
your browser as Chrome make you more unique?

Because trackers aren�t only looking at what browser version you have.
In combination with other metrics, your fake Chrome browser may stand
out. This is because if you are actually using, say, Safari browser all
the other metrics will point to this fact. You will have the only
browser out there identifying itself as Chrome but looking like Safari.
Incognito mode

Historically, Private Browsing and Incognito Mode had a single purpose.
These modes were intended to prevent traces of sites you visited from
being stored on your machine. It was not meant to prevent remote sites
or trackers from identifying and storing when you visit a site on their
servers.

If you are using Firefox, using Private Browsing will provide some
protections against trackers. Any trackers that are included in the
Disconnect tracking protection list will be blocked. This keeps you
safe from known trackers. Known fingerprinters and cryptominers which
use your browser against you are also blocked. However, this will not
prevent a new fingerprinter or tracker from identifying your browser
and keeping tabs on it. In order to get this extra level of protection,
your browser needs to have a fingerprint which is either:

so common that a tracker can't tell you apart from the crowd (as in
Tor Browser), or
randomized so that a tracker can't tell it's you from one moment to
the next (as in Brave browser).