Cookies and User Tracking:
Cookies are small text files that are stored on a user’s device by websites they visit. These files contain information about the user’s interactions with the website and are primarily used for tracking and personalization purposes. While cookies can be helpful in enhancing the user experience, they can also be used to track user activity even if their browsing history has been deleted. Here’s how cookies can show that a user has visited a site, despite the deletion of their browsing history:

Persistent Cookies: Persistent cookies are designed to remain on a user’s device for an extended period, even after the browser is closed. These cookies have an expiration date set by the website and are stored in a specific location on the user’s device. Even if a user deletes their browsing history, persistent cookies will still exist on their device until they reach their expiration date.

Third-Party Cookies: Many websites incorporate third-party services, such as advertising networks or analytics platforms, which can set their own cookies on the user’s device. These third-party cookies can track user activity across multiple websites, creating a profile of their browsing behavior. Even if a user deletes their browsing history, these third-party cookies may still be present and able to track their visits to specific sites.

Cookie Syncing: Cookie syncing is a process where different advertising networks or tracking services share cookie information to create a comprehensive profile of a user’s online activity. This allows them to track users across multiple websites and display targeted ads. Even if a user deletes their browsing history, cookie syncing can still establish connections between sites visited and the user’s profile, reflecting their previous interactions.

Cross-Device Tracking: With the proliferation of mobile devices, users often access websites from multiple devices. Cookies can be used for cross-device tracking, linking a user’s activity across different devices to create a unified profile. Even if a user deletes their browsing history on one device, cookies on other devices may still indicate their previous visits to specific sites.

Local Storage and IndexedDB: In addition to cookies, websites can also utilize other storage mechanisms like local storage or IndexedDB to store data on a user’s device. These storage methods are not affected by deleting browsing history and can continue to hold information about a user’s previous visits to a website.

In summary, cookies can show that a user has visited a site even if their browsing history has been deleted due to the presence of persistent cookies, third-party cookies, cookie syncing, cross-device tracking, and other storage mechanisms like local storage or IndexedDB. These tracking methods enable websites and advertisers to gather information about users’ online behavior and deliver personalized experiences or targeted advertisements based on their past interactions.