Yahoo Mail

"We may recognize you or your devices even if you are not signed in to our Services. Yahoo may use device IDs, cookies, and other signals, including information obtained from third parties, to associate accounts and/or devices with you. ... Associate your activity across our Services and your different devices as well as associate any accounts you may use across Yahoo Services together. We may associate activity and accounts under a single user ID."

Yahoo tracks users across devices and services, linking activity into a unified profile using device IDs, cookies, and third-party signals — even when the user is not signed in.

"Location Information. We collect location information from a variety of sources. You can learn more about and manage your location permissions on our Locations page and by visiting the location settings tool on your devices."

Yahoo collects location data from multiple unspecified sources, and uses it for location-based advertising and content. The vague language ('a variety of sources') obscures exactly how pervasively location is tracked.

"We allow other companies that show advertisements on our webpages or apps to collect information from your browsers or devices. Other companies' use of cookies and other data collection technologies are subject to their own privacy policies, not this one. ... We provide user information to or enable the collection of user information by trusted partners who work on behalf of or with Yahoo."

Yahoo allows third-party advertisers to directly collect data from users' browsers and devices on Yahoo properties, governed by those third parties' own policies rather than Yahoo's.

"Device Information. We collect information from your devices (computers, mobile phones, tablets, etc.), including information about how you interact with our Services and those of our third-party partners and information that allows us to recognize and associate your activity across devices and Services. This information includes device specific identifiers and information such as IP address, cookie information, mobile device and advertising identifiers, browser version, operating system type and version, mobile network information, device settings, and software data."

Yahoo collects a broad range of device data including advertising identifiers, device settings, mobile network information, and software data — going well beyond what's needed for core service delivery.

"Yahoo will retain your personal information for as long as necessary to provide the applicable Yahoo Services to you. In some cases, Yahoo has certain business or legal requirements that result in an obligation to retain your personal information for an extended period of time. ... In some limited cases, we may keep data for longer than needed for the purposes set out in the Yahoo Privacy Dashboard, such as: (i) replicating or backing up certain data to 'offline' storage for disaster recovery purposes; ... (iii) maintaining de-identified data for varying periods for research, reporting and product testing or development."

Yahoo has no clear deletion timeline and lists multiple broad exceptions allowing indefinite retention — including disaster recovery backups, statistical aggregation, research, and legal compliance — with no specified time limits.

"We may update this Privacy Policy from time to time, so you should check it periodically. If we make changes that are material we will provide you with appropriate notice before such changes take effect."

Yahoo reserves the right to change the privacy policy at any time, with only a vague promise of 'appropriate notice' for material changes and an expectation that users periodically check for updates themselves.