UID2 and the post-cookie identity playbook for Australian advertisers
Unified ID 2.0 replaces the third-party cookie with a privacy-conscious identifier built from consented first-party data, letting Australian advertisers target and measure across devices and channels, including CTV, where cookies never worked.
Third-party cookies are no longer a foundation you can build on. Browser restrictions, mobile identifier changes and tightening privacy expectations in Australia mean the old way of tracking and targeting users across the web is fading. Unified ID 2.0 (UID2) is the industry’s most widely adopted answer, and for Australian advertisers it’s an opportunity to build targeting on a stronger, more durable foundation than cookies ever offered.
What is Unified ID 2.0?
Unified ID 2.0 is an open-source, industry-governed framework for identity in advertising. Instead of relying on a third-party cookie, it creates a privacy-conscious identifier derived from a piece of authenticated, consented first-party data, most commonly a hashed and encrypted email address or phone number. The raw email is never exposed; it’s transformed into a token that can be used to recognise and reach an audience across channels and devices.
Crucially, UID2 is not owned by a single platform. It’s an open standard, which is why it has been adopted broadly across the open internet, including connected TV and streaming where cookies never worked in the first place.
Why cookies are no longer enough
- Coverage gaps: cookies don’t function in apps, on connected TV, or in many mobile environments, a growing share of media consumption in Australia.
- Browser restrictions: major browsers limit or block third-party cookies, fragmenting audiences and inflating frequency.
- Measurement breakdown: without a consistent identifier, you can’t connect an impression on one device to an action on another.
The challenge of a post-cookie world is real, but it’s also the moment to stop renting audience signal from third parties and start building it from data you own.
How UID2 works, step by step
- A user provides consent and an authenticated identifier (e.g. logs in with an email).
- That identifier is hashed and encrypted, and the raw value is never shared with advertising platforms.
- The resulting token (a UID2) can be activated across the open internet: CTV, audio, display, native and more.
- The same token underpins measurement, so exposure and outcomes can be connected across devices.
Building your first-party data foundation
UID2 is only as strong as the data feeding it. For most Australian brands, the priority is growing authenticated, consented first-party relationships:
- Capture more logged-in or identified interactions: accounts, newsletters, loyalty programs, purchase records.
- Make consent clear and valuable: people share data when they understand the exchange and trust the brand.
- Onboard historical records: existing customer and enquiry data can become a seed audience for lookalike modelling of in-market prospects.
What this means for your media
With a UID2 foundation in place, you can build seed audiences from known customers, model lookalikes of high-value prospects, maintain consistent frequency across devices, and measure outcomes that cookies could never see, particularly on CTV and audio. The practical payoff is less wasted spend and a clearer line between media investment and business result.
| Third-party cookies | Unified ID 2.0 | |
|---|---|---|
| Works on CTV / apps | No | Yes |
| Cross-device | Limited | Yes |
| Based on | Browser tracking | Consented first-party data |
| Owned by | Third parties | Open industry standard |
Getting started
You don’t need to solve everything at once. Start by auditing how much authenticated first-party data you currently capture, identify where you can grow consented relationships, and work with a media partner who can activate UID2 across the channels that matter to your audience. The brands that build this foundation now will have a durable advantage as the open internet moves fully past the cookie.
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Frequently asked questions
What is Unified ID 2.0 (UID2)?
Unified ID 2.0 is an open-source, industry-governed identity framework for advertising. It creates a privacy-conscious, encrypted identifier from consented first-party data such as a hashed email address, allowing advertisers to reach and measure audiences across channels and devices without third-party cookies.
Is UID2 privacy-safe?
UID2 is built around user consent and encryption. The raw email or phone number is never exposed to advertising platforms. It is hashed and encrypted into a token. Users can opt out, and the framework is governed as an open industry standard rather than controlled by one company.
Why do advertisers need an alternative to third-party cookies?
Third-party cookies don’t work in apps or on connected TV, are increasingly blocked by browsers, and can’t reliably connect activity across devices. This fragments audiences, inflates frequency and breaks measurement. UID2 addresses these gaps using consented first-party data.
How do I prepare my brand for a post-cookie world?
Focus on growing authenticated, consented first-party data through accounts, loyalty programs, newsletters and purchase records, then onboard it into an identity framework like UID2 to build seed and lookalike audiences and enable cross-device measurement.
Key Takeaways
- Unified ID 2.0 replaces the third-party cookie with a privacy-conscious identifier using consented first-party data.
- This framework allows Australian advertisers to target users across devices and channels, including CTV, where cookies failed.
- UID2 creates a hashed and encrypted identifier, ensuring user information remains private and is not disclosed to advertising platforms.
- Advertisers should build first-party data foundations by capturing logged-in interactions and making consent clear and valuable.
- With UID2, brands can efficiently measure outcomes, build seed audiences, and improve targeting without relying on third-party cookies.