Add structure, terms and scope and methodology

introduction.tex

@@ -25,4 +25,61 @@ used to track individuals on the Internet and which countermeasures exist?}
 \section{Terms and Scope}
 \label{sec:terms and scope}
 
+This thesis will focus on web tracking as employed by for example advertising
+companies. When users visit a web site which uses third party content from
+advertisers, those advertisers collect bits of information about the user. These
+bits of information are not yet associated with a particular user but with an
+online identity which is usually tied to a unique identifier. The unique
+identifiers are by themselves not meaningful because the same user might get
+multiple unique identifiers, each corresponding to other bits of information. To
+allow the series of information to be aggregated into one profile which
+approximates a user's personality, needs and wants, tracking mechanisms are
+used. In many cases the goal is to persist tracking identifiers on the user's
+computer for as long as possible and to not assign multiple identifiers to the
+same person.
 
+The tracking mechanisms presented in this work are mechanisms which store
+information on the user's computer. They are---in other words---\emph{stateful}
+mechanisms. Such mechanisms include \gls{HTTP} cookies or various forms of
+caches. Contrary to stateful mechanisms, \emph{stateless} mechanisms do not
+store information on the user's computer but attempt to infer information by
+reading the browser state. This can mean knowing which fonts are installed and
+inferring that a particular user is using a Windows operating system instead of
+Linux or that they are visiting with a mobile browser and not from a desktop.
+This type of tracking is also called \emph{device fingerprinting}. With enough
+fingerprints, trackers can uniquely identify a user or device by knowing that no
+other entity uses the Internet with the same unique fingerprint.  Stateless
+tracking mechanisms are not discussed in this work, instead the focus will be on
+stateful tracking mechanisms.
+
+\section{Methodology}
+\label{sec:methodology}
+
+This work gives an overview of tracking methods and defenses which have been
+studied in the literature. As such, a comprehensive literature review of
+relevant research is performed, with a focus on recent developments. Papers will
+be collected through the usage of digital libraries and search engines such as
+the \emph{ACM Digital Library}, the \emph{IEEE Xplore Library}, \emph{Google
+Scholar} and for selected works to appear in peer-reviewed journals
+\emph{arXiv.org}. Additionally, well-known journals and proceedings like
+\emph{Computers \& Security} and \emph{Proceedings on Privacy Enhancing
+Technologies} are manually searched for relevant papers. The used search terms
+include but are not limited to keywords such as \emph{Stateful Web Tracking},
+\emph{Web Tracking}, \emph{Tracking Measurement} and variants thereof.
+Furthermore, queries for the names of particular tracking methods are made. For
+information on \emph{Cookie Synchronization} (section~\ref{subsec:cookie
+synchronization}) for instance, separate search queries will be performed.
+
+\section{Structure of the Thesis}
+\label{sec:structure of the thesis}
+
+The thesis is divided into two major parts: chapter~\ref{chap:tracking methods}
+is concerned with how web sites on the Internet track individuals and
+chapter~\ref{chap:defenses against tracking} offers users ways to defend
+themselves against those tracking methods. Chapter~\ref{chap:tracking methods}
+is split into three parts, each focussing on a subset of tracking methods that
+can be grouped together. The chapter on defenses against tracking first presents
+ways in which users can use existing browser features to limit tracking. The
+second part discusses specialized tools which focus on one aspect of tracking
+and summarizes research concerned with the effectiveness of these tools. The
+thesis is concluded in chapter~\ref{chap:conclusion}.