\chapter{Conclusion}
\label{chap:conclusion}

Web tracking is an increasing concern of individual users trying to protect
their privacy. They see themselves fighting against a conglomerate of tracking
companies that seek to sell big amounts of personal user data. Once harmless and
well-intentioned mechanisms such as \gls{HTTP} cookies have been repurposed over
time to serve the interests of those companies, often times at the expense of
individual users. Legitimate uses of tracking on the Internet such as for
personalizing search results or offering adequate recommendations for shopping
and entertainment have brought with themselves a myriad of other possibilities
to use user data. Since opting-out of the collection of \gls{PII} is usually not
possible, tools to combat privacy invasion via tracking have been and are still
developed. These tools offer users a chance to protect themselves to a degree
which they seem fit as long as they possess the knowledge to do so.

This thesis serves as an introduction to tracking on the Internet. Various forms
of online tracking have been discussed and their functionality explained. For
every method its occurrence on the Web has been quantified, giving users an
overview of which methods are more widespread and which less. Furthermore,
an objective evaluation of each method with respect to the impact on users'
privacy is given, allowing users to make a well-founded threat assessment for
their individual use case and preference.

In chapter~\ref{chap:defenses against tracking}, users are given the tools to
defend themselves against the previously discussed tracking methods. The
advantages and disadvantages of each tool are presented and common
misconceptions are dealt with. Additionally, it becomes clear that users have to
make tradeoffs between privacy and ease of use, where more privacy often results
in not being able to visit certain sites (for example when disabling
JavaScript).

The arms race between tracking and advertising companies and users will continue
for the foreseeable future. For individuals achieving full protection against
any and all trackers is practically impossible even today. This will continue
further as long as consumers give their privacy away for supposedly \emph{free}
services and governments do not impose severe penalties on privacy violations
not only on paper but by following through on them. Until then, only
knowledgeable users will be able to defend themselves and it will get harder
with every passing year.
