As ID bridging emerges as a potential successor to third-party cookies, industry stakeholders are grappling with issues of transparency, privacy, and fraud.
With third-party cookies on the decline, digital advertisers are exploring alternatives that protect user privacy while enabling effective ad targeting. Google’s early 2024 move to remove cookies for 1% of users signals the beginning of the industry’s shift toward a cookieless era. This change has driven advertisers to solutions like ID bridging, which uses persistent identifiers, such as hashed emails and device IDs, to facilitate tracking without traditional cookies. Although ID bridging presents opportunities for privacy-compliant tracking, its use raises significant concerns around scalability, accuracy, and fraud potential. Many demand-side platforms (DSPs) view ID bridging as a sophisticated form of invalid traffic, pointing out risks associated with mismatched or spoofed IDs. This ambiguity has sparked concerns over campaign performance and accuracy, complicating marketing strategies.
ID Bridging vs. Cookies
Traditional cookies offer browser-specific, short-lived tracking that has limitations, particularly in cross-device targeting. However, ID bridging, which employs identifiers like hashed emails and device IDs, enables more consistent, cross-channel targeting that complies with privacy standards. This approach also allows digital publishers to synchronize audience data across different platforms, creating a consistent user experience even in cookieless environments like Apple’s Safari.
Challenges and Opportunities in ID Bridging
Despite its potential, ID bridging involves complexities tied to deterministic and probabilistic matching. Deterministic methods rely on identifiers like hashed emails, ensuring consistency but dependent on user logins across platforms. Probabilistic matching, which uses signals like device type and IP addresses, broadens reach but may sacrifice some accuracy. Concerns over transparency and fraud prompt agencies and brands to adopt protective measures, such as direct relationships through supply path optimization (SPO), using resources like ads.txt and sellers.json to ensure reliable sourcing.
However, not all industry leaders endorse ID bridging. Niall Hogan, general manager of JAPAC at GumGum, describes it as an effort to sidestep privacy policies designed to protect user data. Hogan advocates for contextual advertising as a more privacy-friendly approach, enabling brands to target users based on relevant content rather than identity-based tracking.
The Future of ID Bridging
The future of ID bridging is uncertain, though recent steps toward transparency offer hope. In May 2024, the IAB Tech Lab brought together industry stakeholders, releasing updated OpenRTB specifications in September to increase clarity around bridged ID sources. These updates help advertisers assess ID quality, potentially allowing reallocation of budgets toward more reliable data sources. According to Anoop Ramachandran, CTO at Preciso, “The new ID origin fields increase confidence in cross-device targeting, enabling advertisers to distinguish between deterministic and probabilistic bridged IDs and optimize accordingly.”
As the industry awaits further clarity, experts advise advertisers to approach ID bridging cautiously, given ongoing debates over its accuracy and scalability. The recent updates are a step toward greater transparency, yet questions remain about the long-term viability and effectiveness of ID bridging for precise, privacy-compliant targeting.
