Third-party cookies are types of tracking codes placed on a user's computer by a website other than the one being visited. As internet users browse, a third party will deposit a code on their hard drive that gathers information about the user and their online activity. Examples of information gathered by third-party cookies may include:
- Identification of users
- Visited website names
- Age, gender, and demographics
- Personalization preferences
Third-party cookies are extremely useful to marketers and advertisers alike. By understanding a user's online behavior, companies can more effectively target their ads and craft personalized messages that appear more enticing to audiences. Some third-party cookies even allow for cross-device tracking, allowing domains to monitor a user's activity across multiple devices (laptops, tablets, smartphones, and more).
The vast majority of third-party cookies are not used for malicious intent. However, their ability to be hijacked by ill-intentioned persons has made them a point of contention among private citizens. Today, most internet browsers block third-party cookies by default. Major browsers intend to phase out third-party cookies entirely within the next few years.