Purging programmatic of persistent IDs

6th March  |  
4 minutes
persistent ids

2024 will go down as a landmark year in the progress towards a more privacy-centric internet. By the end of this year, all going well, tracking cookies will have been removed from Chrome. Having already been deprecated in Safari, Edge, and Firefox, Google’s move marks the end of the use of invasive third-party cookies in internet browsers. However, while a significant step forward, the end of tracking cookies doesn’t mean the end of all persistent IDs. If programmatic advertising is to adapt to a privacy-conscious age, then it must purge itself of all forms of persistent ID.

What are persistent IDs?

Persistent identifiers are any unique identifier that tracks the activities of people or devices across the internet over time. Persistent IDs enable publishers and advertisers to track user behaviour, preferences, and interactions across different websites and online platforms to facilitate personalised, real-time programmatic advertising campaigns.

Tracking cookies are just one form of persistent ID. Others that will remain following cookie deprecation include device IDs, which are unique identifiers assigned to mobile devices or tablets; user IDs, which track users through account login data; and fingerprinting, which combines various attributes of a device (such as browser type, operating system, installed fonts, screen resolution, and more) to create a unique identifier.

How do persistent identifiers work?

Persistent identifiers deliver a single view of a user across all their devices using the deterministic data outlined above. If a persistent ID is to deliver an audience for use in programmatic advertising, publishers must either map their data to their inventory, or their ID to other buy-side segmented audience IDs. Persistent IDs are offered to advertisers either by the publisher themselves or via Supply-Side Platforms (SSPs).

What are the privacy concerns around persistent IDs?  

The key challenge with persistent IDs from a privacy perspective is that the deterministic data used to build the ID (device data, login data, and the data used in fingerprinting) can ultimately be tied to a recognised individual. Unless that individual has given explicit consent for their data to be used in this way, it is a breach of their privacy. This can be an issue as the mechanisms for obtaining user consent are often unclear, misleading, or buried in lengthy privacy policies that few read or understand.

The longevity of persistent IDs is also a challenge. A user may well consent for their data to be used to create an advertising ID in a specific context. However, as the ID persists in the programmatic supply chain, it has the potential to be reused time and again without the data owner giving consent, or even being aware the ID is still active.

What can replace persistent IDs?

Given the significant privacy concerns around persistent IDs, it’s imperative that publishers, advertisers, and adtech businesses curtail their use.

Fortunately, privacy-first alternatives exist that can provide the audience insights and reach needed to deliver real-time personalised advertising programmatically. Dynamic identifiers, such as Novatiq’s Hyper ID, are a case in point. Dynamic IDs are transient, meaning they only last during the targeted advertising placement process. Dynamic IDs, which are generated by a telco using their network intelligence, are applied for each individual ad request. As a result, dynamic IDs are by nature one-off and non-sequential, which makes it impossible for the audience data to be reused.

How do dynamic IDs work?

Dynamic IDs sit within a telco network and rely on their first-party deterministic data. When an advertiser requests an audience segment, the telco matches the segment attributes in real-time to the request and assigns a dynamic ID. The ID is then securely guided across the programmatic ecosystem so it can be exchanged for associated segments at point of use. Once this process is complete, the ID becomes inactive.

The transience of dynamic IDs means that data owners’ consent is always respected. What’s more, as no personal data is transmitted into the programmatic ecosystem, they are privacy-centric by design. By leveraging such IDs, the digital advertising ecosystem can deprecate all persistent IDs and put the industry on a privacy-centric path.

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