The article focuses on how various online identifiers, like cookies and device information, are used to track user activity across apps and websites. These tools help vendors recognize returning users, enabling personalized advertising. When a user visits a site, a cookie is stored on their device, allowing for targeted ads. For instance, a car manufacturer can advertise electric vehicles to users in urban areas after work hours, while a watercolour paint producer targets ads to artists based on their browsing habits. The piece highlights how data collected from user interactions is used to create profiles for more relevant advertising. If you frequently read about bike accessories, your profile might suggest an interest in luxury cycling gear if you also explore high-end car websites. Advertisers use this information to refine their campaigns, aiming to reach specific audiences effectively. Statistics and audience analysis play a crucial role in this process. Advertisers can generate reports that reveal user behavior patterns, such as the ratio of visitors who buy versus those who leave a site without purchasing. This data helps businesses understand their audience better and tailor their marketing strategies accordingly. The article emphasizes the extent of data retention, noting that information can be stored for up to 400 days for various purposes, including advertising performance measurement and service improvement.