This thesis examines the application of traditional jurisdictional doctrines to online activity. It analyses not only to what extent, and why, the Internet challenges existing principles allocating regulatory competence, but the factors which shape, and must shape, the regulatory responses to these challenges, in an attempt to create an analytical framework within which the search for viable solutions can begin. The overarching argument made in this thesis is that the keys to viable future Internet regulation are deeply embedded in past and present regulation and that we cannot simply look for the most efficient legal solutions, regardless of how they fit within existing laws. This would be inconsistent with the law's basic function to answer the need for certainty and predictability. Building upon this fundamental premise, it is further argued, and shown, that an understanding of the public law - private law dichotomy within the existing jurisdictional framework, as well as its deeply entrenched status, is essential for appreciating the severity of the jurisdictional problems caused by the Internet and actual and likely regulatory responses to them. It is argued that this explains why both sets of rules have consistently accommodated transnational online activity differently, giving rise to different problems - problems which ultimately touch upon fundamental legal notions, such as formal justice, the rule of law or obedience to law which cannot but set further outer parameters of the search for solutions to the jurisdictional problems triggered by the Internet.