August 9, 2025
2 min read
The analysis of first-party and third-party cookies reveals distinct differences in their creation, application, and privacy implications. First-party cookies are set directly by the website a user actively visits. These cookies are accessible only to the domain that created them, primarily serving to enhance user experience through the storage of session state, login information, and preferences (Sanchez-Rola et al., 2019). For instance, first-party cookies enable features like “remember me” on login forms or retaining items in a shopping cart across sessions.
Conversely, third-party cookies originate from domains other than the one displayed in the browser’s address bar, typically embedded through advertisements, social media widgets, or analytics scripts. These cookies track users across multiple domains, enabling extensive behavioral profiling and ad retargeting (Englehardt & Narayanan, 2016). The core distinction is articulated in the following comparative points:
| Feature | First-party cookies | Third-party cookies |
|---|---|---|
| Set by | Website publisher | Affiliate networks/advertisers |
| Purpose | Improve user experience | Retarget users with custom ads |
| Tracking scope | Single domain | Across multiple domains |
| Data access | Only by visited website | By external domains and advertisers |
| Disabling method | Browser settings | Browser settings |
Empirical studies demonstrate that third-party cookies contribute disproportionately to creating comprehensive user profiles, often without explicit consent (Roesner et al., 2012). Recent browser updates, such as Safari’s Intelligent Tracking Prevention and Firefox’s Enhanced Tracking Protection, now block third-party cookies by default. This trend reflects a growing recognition of privacy risks associated with cross-site tracking.
In summary, while both cookie types technically function as browser-based storage mechanisms, their differentiation lies in ownership, scope of tracking, and privacy impact. The implications for user privacy and digital advertising are significant, driving regulatory and technological changes within the web ecosystem (Sanchez-Rola et al., 2019; Englehardt & Narayanan, 2016).
