SharedID stores a pseudonymous user identifier in first-party cookie storage via Prebid's UserID Module framework.
SharedID with Prebid.js was a free identity solution owned by the community rather than a vendor, delivers the trust and transparency required for widespread adoption across publishers and marketers and their agents.
One benefit of SharedID is that cookie syncing becomes unnecessary as every party uses the same interoperable pseudonymous identifier.
As of Prebid.js 5.0, two changes were made:
- PubCommon ID is no longer supported, but replaced by SharedID.
- SharedID no longer syncs to SharedID.org to ensure a consistent cross-site identifier, but now relies on a random user ID per domain.
Given these changes, buyers will likely migrate their use to more useful addressable media identifiers.
More information can be found at https://docs.prebid.org/identity/sharedid.html