The document introduces the concepts of behavioural targeting, personalisation, and online marketing optimisation. It provides examples of how behavioural targeting can improve the effectiveness of advertising campaigns by serving customized ads to users based on their interests and online behavior. Personalisation is defined as delivering targeted content and adaptive experiences based on a user's profile and past actions. Examples are given of how major companies like Yahoo and search engines personalize search results and recommendations based on a user's history and preferences. The goals of these techniques are to improve the effectiveness and efficiency of marketing strategies.