diff --git a/sections/line-wrap.tex b/sections/line-wrap.tex
new file mode 100644
index 0000000..eaeefd5
--- /dev/null
+++ b/sections/line-wrap.tex
@@ -0,0 +1,11 @@
+\section{Rule number 4: line wrap}
+\begin{frame}{Leave space for the receving end}
+    Both the LKML netiquette~\cite{netiquette:lkml} and RFC 2822~\cite{rfc2822} suggest to wrap lines at 78 characters.\vspace{1em}
+
+    \begin{quote}
+        Text-based e-mail should not exceed 80 columns per line of text. Consult the documentation of your e-mail client to enable proper line breaks around column 78.
+    \end{quote}
+\end{frame}
+\begin{frame}{How to (Thunderbird/Neomutt)}
+    Both Neomutt and Thunderbird automatically default to wrapping lines after 72 characters when plain text mode is enabled.
+\end{frame}
diff --git a/slides.tex b/slides.tex
index a96475b..0878972 100644
--- a/slides.tex
+++ b/slides.tex
@@ -24,6 +24,7 @@
     \input{sections/signature}
     \input{sections/plain-text}
     \input{sections/top-posting}
+    \input{sections/line-wrap}
 
     \nocite{*}
     \bibliography{refs}