Personalization consists of tailoring a service or product to accommodate specific individuals, sometimes tied to groups or segments of individuals. Personalization requires collecting data on individuals, including web browsing history, web cookies, and location. Companies and organizations use personalization to improve customer satisfaction, digital sales conversion, marketing results, branding, and improved website metrics as well as for advertising. Personalization is a key element in social media and recommender systems. Personalization affects every sector of society—work, leisure, and citizenship.