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--- privacy:cookies [2025/06/05 15:12] – [CookieBlock Model] typo karelkubicek
+++ privacy:cookies [2026/08/31 19:48] (current) – Add one sentence pointing to the new Privacy:Browser storage page for persistence that is not a Set-Cookie. Authored by Claude karel.kubicek.claude
@@ Line 1: / Line 1: @@
 ====== Classifying Cookies ======
-Browser cookies are still the most commonly used method for tracking the session state of websites and the identity of visitors. According to prior studies, between 80% in 2012 {[roesner2012_detecting]} and 90% in 2019 {[solomos2019_clash,sanchezrola2019can]} of websites use cookies for user tracking, often without users' knowledge. While other stateless tracking technologies, such as [[Privacy:Fingerprinting]] or [[Privacy:Requests#classification_of_link_decorators|Link decorators]], exist, cookies remain the primary choice, with stateless methods typically used in combination with cookies. This trend persists despite the discontinuation of third-party cookies.
+Browser cookies are still the most commonly used method for tracking the session state of websites and the identity of visitors. According to prior studies, between 80% in 2012 {[roesner2012_detecting]} and 90% in 2019 {[solomos2019_clash,sanchezrola2019can]} of websites use cookies for user tracking, often without users' knowledge. While other stateless tracking technologies, such as [[Privacy:Fingerprinting]] or [[Privacy:Requests#classification_of_link_decorators|Link decorators]], exist, cookies remain the primary choice, with stateless methods typically used in combination with cookies. This trend persists, and third-party cookies were in the end **not** discontinued: on 22 April 2025 Google announced it would "maintain our current approach to offering users third-party cookie choice in Chrome, and will not be rolling out a new standalone prompt for third-party cookies".((Privacy Sandbox, [[https://privacysandbox.com/news/privacy-sandbox-next-steps/|"Next steps for Privacy Sandbox and tracking protections in Chrome"]], 22 April 2025. Checked 2026-08-19.)) They remain allowed by default in Chrome, blocked in its Incognito mode, and partitioned per top-level site by default in Firefox and Safari — so what a measurement observes depends on which browser it drove and in which mode; see [[Programming:Stateful stateless#Since 2022 the engine decides, not you]].
 Below, we discuss two main classification methods: using datasets of labeled cookies or machine learning (ML) to classify cookies based on their context and request URL. But first some preliminaries.
+This page is about cookies. A site can persist an identifier in several other places — ''localStorage'' and ''sessionStorage'', IndexedDB, Cache Storage behind a service worker, and the HTTP and favicon caches — and a crawler that records only cookies sees none of them; that is [[Privacy:Browser storage]].
 ===== First- and Third-Party Cookies =====