Fenced Frames
Google's Fenced Frames loads ads in a separate container that dissociates information within the container from the parent page.[1]
Fenced Frames are designed to address short comings in other Privacy Sandbox proposals, such as providing support for:
- Interest Based Advertising
- Conversion Lift measurement studies
- Granting unpartitioned storage access without impairing user experience via a permission prompt
- Cross-site embedded content
Fenced Frames will allow read-only access to cross-site information (e.g., audience segments, membership within an A/B experiment, access to cross-site conversion lift measurement). The Fenced Frame will only have network access beyond the web client, when initiated by a user (e.g., a click).
Chrome recommends caching embedded content to eliminate content access requests at run-time, which thus requires all permutations of personalization logic to be pre-rendered and available to local storage. Chrome calls this pre-rendered content "web bundles".
Impact
By removing communication between the container and the parent page, publishers lose monitoring and control over this content.
Fenced Frames suggests that Chrome will allow people choice to store information in their browser that can be used across different sites. "On user activation / [Fenced Frame will have] Full network access, read/write unpartitioned storage (if requested [from the user)"[2] However, a per ad slot pop-up dialog seems like a poor user experience.
If the parent page cannot know or communicate information into Fenced Frame, it is unclear how resizing, scrolling or other user actions in the parent page will avoid causing a poor user experience with the content within the frame.