== Tracking We Will Block ==
===== 1. CrossStateful cross-site tracking through Web APIs =====
'''Cookie-based cross-site tracking.''' Cookies, DOM storage, and other types of stateful identifiers are often used by third parties to associate browsing across multiple websites with the same user and to build profiles of those users, in violation of the user’s expectation.
For third parties engaged in this type of tracking, Firefox will block or remove access to stateful identifiers. Access to storage may be granted when a user has shown purposeful intent to interact with a third party during their visit to a specific first party. For example, if a user attempts to interact with a third-party login provider while visiting a specific first party, the third-party provider may receive storage access on that first party.
'''URL parameter-based ===== 2. Navigational cross-site tracking.''' When cookie-based tracking is not available, some third parties decorate URLs with user identifiers. When the browser requests those resources, either through a top-level navigation or a subresource request, those user identifiers are available to other websites or third parties. Any party actively setting, retrieving, or sharing an identifier or other personal data in a URL parameter for the purpose of building a user profile is in violation of this policy. While this type of tracking is not currently blocked in Firefox, we may apply additional restrictions to the third parties engaged in this type of tracking in future. =====
'''URL parameter-based cross-site measurement, such as ad conversion tracking.''' When cookie-based tracking is not available, is acceptable only when some third parties decorate URLs with user identifiers. When the data collected is not tied browser requests those resources, either through a top-level navigation or a subresource request, those user identifiers are available to other websites or third parties. Any party actively setting, retrieving, or sharing an individual user, and therefore doesn’t allow identifier or other personal data in a URL for the data collector to build purpose of building a user profile is in violation of an individual user’s activity across sitesthis policy. Firefox will blocklist parameters included in the URL for this purpose and remove them from cross-site top-level navigations.
::''Acceptable Example:''::A site wishes to track conversions after a user interacts with an ad. The site can annotate User profile building is currently characterized by Firefox through the landing page URI of outbound advertisements clicks with information about which advertisement was clicked and from which publisher. When a user later completes a conversion action, thirdfollowing client-party code from the site transfers information about the advertisement that led to the conversion back to its servers, such that an aggregate number of conversions can be computed. This is acceptable under our policy because it does not involve the creation of a user profile. observable traits:
::* High-entropy parameters that may identify a user (assign a unique identifier to a user) or encode user data. '''Unacceptable ExampleExceptions being:'''::Similar to ** Parameters exclusively identifying specific elements or actions on the example above, site A wishes to track conversionsnavigating page (per-click or per-element identifiers). But unlike that example, site A decorates all outbound links with These parameters must assign a unique identifier that is mapped back different value to an individual usereach click or element they are identifying. A ** Identifiers necessary to complete a user clicks on -initiated task such as logging in or submitting a search result for site B and later purchases form.* High-entropy parameters that are broadly included in all (or nearly all) outgoing navigations from a product from site B. When this purchase is completed, even if the user’s unique identifier is sent back to site A’s servers to record the purchaseparameters are not uniquely identifying a user. Due to the fact that site A is building a profile Because any type of URL decoration can violate some users’ personal sense of user purchasesprivacy, this approach goes beyond conversion measurement we allow for optionally configuring Firefox to apply stricter rules for parameter removal and would be may remove more parameters on certain user actions such as sharing a violation of this policyURL.
Firefox may also apply stricter rules for parameter removal by default in the future, which will be reflected in this policy. ===== 23. Tracking via unintended identification techniques =====
'''Unintended identification techniques''' use browser features that are not intended for device or user identification for the purposes of storing or generating a tracking identifier. Unlike tracking using standards-defined storage locations - such as cookies or the Web Storage API - these techniques are not under the control of the browser’s state management settings.Thus can not be easily cleared or reset by users. Examples include, but are not limited to:
