Within 24 hours of visiting a website (for instance Facebook), cookies from that site can be used on another site. This allows you to do things like post comments using your Facebook profile on a third-party website.



After 24 hours have passed since you visited a website, its cookies become unavailable for use on other websites. In our Facebook example, this means Facebook would not be able to continue tracking your activity around the web — and that you wouldn't be pre-authenticated to use your Facebook credentials for the third-party website's comments. Because its cookies were still being stored (in a secure “silo”), Facebook’s website would still remember your credentials when you you visited facebook.com.



After 30 days, if you have not visited a website, any cookies being stored by that site are then purged entirely.



While Google is off building new ways to make more money out of the personal data they collect from their users, Apple — a direct competitor in certain areas — is seeking out methods to further protect their customers from being tracked online. WebKit, the framework behind the Safari Browser, is launching a feature called Intelligent Tracking Prevention which works to limit cookies and other ways websites track their visitors. This feature protects Safari’s users as well as improving their experience online — trackers can expose personal browsing activity and bloat the time it takes to load a page.Popular websites you visit every day utilize something called cross-tracking and third party cookies. This means if you’re shopping on macys.com, then switch to amazon.com, your browser will have stored third party cookies that allow Amazon to know exactly what you were looking for at Macy’s, impacting the products and prices you see. Airlines take similar actions when users are comparing prices for fares — tracking your destinations, dates traveling and sites visited will then alter the fare prices the longer you search.Although it sounds innocent enough, websites are constantly collecting data about your online habits and then sharing it with other companies. Safari’s Intelligent Tracking Prevention protects you somewhat from this unwarranted invasion.This new feature collects information from page loads and user interactions and stores it in a silo for each privately-controlled domain name. When you visit a site, WebKit classifies whether that domain name tracks users, and keeps track of how recently you interacted with that domain. Information is then purged on a set timeline:Over time, this ensures that the only cookies tracking your behavior are from the sites you use most, whereas everything else is automatically dumped without you having to worry about it.Apple is aware that websites need on-device storage such as cookies in order to provide the optimal user experience — their goal is to strike a healthy balance between this reality and your privacy. For more information, check out WebKit’s official article announcing this Intelligent Tracking Prevention feature.