After a brief introduction, Crystal devotes two chapters to what he calls "Netspeak", looking at features common to most Internet communications. He compares this to speech and writing and argues that it is different enough to be a genuine "third medium". He also considers some broad pragmatic themes (communicative effectiveness, spamming, lurking), the limitations of Net style guides (which often lapse into prescriptivism, even when they are prescribing idiosyncrasy), and some widely occurring features (such as emoticons and abbreviations).
Crystal continues with separate chapters on email, chatgroups, virtual worlds, and the Web, and even within those he is mindful of the diversity of Internet users and communities. He is also open about the limitations, in both quantity and quality, of the linguistic work that has been done on Internet language — his presentation is heavily reliant on his personal experience, for example for statistics and generalisations about email, and a few key studies, such as Lynn Cherny's work on ElseMoo. A closing chapter looks briefly at the effects of the Internet on broader language, and at the use of the Internet by linguists and language students.