In July, we heard that the hard cut of Google Chrome 3rd-party cookies had been cancelled. So, does it make sense to continue testing and implementing Privacy Sandbox solutions like the Topics API? Well, you never know what Chrome's next move will be. Still, based on the information available when writing this post, Chrome will continue to focus on the Privacy Sandbox, and the data we have been collecting suggests that publishers should consider activating Topics for their SSP partners.
How Topics API Works: A Quick Overview
Before diving into the details, here’s a short recap of what the Topics API actually is. In the Privacy Sandbox, Google introduced several new solutions for cookieless ad targeting and campaign measurement. There are two solutions for advertising targeting: Protected Audiences and the Topics API. Protected Audience's aims to replace traditional re-targeting, which, based on tests and news, seems to be quite complicated and challenging. Topics is a significantly simpler and lighter solution, enabling data sharing on audience interest signals without cookies. Topics signals aim to communicate interests, for example, if the user might be interested in travelling, cooking, or fashion. Placing people—or more specifically, browsers—into these segments is done based on their browsing history. There are many interesting details about privacy and technology regarding how this is done. If you would like to dive deeper into these details, the best source of information is Google's documentation, which can be found here.
If an inventory seller uses Google Ad Manager, Topics signals will be shared by default. However, Prebid’s Topics module must be implemented to enable signal sharing with Prebid partners. The ease of implementation and outcome analysis will depend on the tools in place.
Topics API in Action: Initial Findings
We have been sharing Topics signals with our customers through Prebid for a few months, and initial findings suggest that activating Topics makes sense for most. Here is what we have learned from our sample, which consists of ten publishers:
- Publisher eCPM seems to be at the same level with or without Topics included in the bid request. In this sample, there was a tiny uplift in eCPM when Topics were enabled, but the difference was not, at least yet, meaningful.
- However, when considering the fill rate, we start to see a bigger variation between inventory with Topics enabled and inventory without it. Topics-enabled inventory fills significantly better in Prebid, which means a better outcome for publishers’ bottom lines.
- Eight publishers out of the ten in the sample achieved increased revenue per thousand ad requests. Why didn’t it bring an uplift for everyone? Perhaps those two publishers who didn’t see an uplift are already sharing other (more) valuable data points, and Topics signals couldn’t provide additional value for them.
- There was quite a significant range among those eight publishers who saw an uplift. This is speculation at this point, but perhaps those who saw the biggest uplift had not implemented other up-to-date data-signalling solutions, meaning that they were unable to share valuable signals about their audience without Topics.
All in all, the uplift in fill rates was significant for the majority of publishers in this study, leading to this conclusion: enabling Topics in Prebid makes sense. It is not a silver bullet that will skyrocket sales (like nothing is), but it can definitely increase the value of your inventory. The easiest way to find out if it works for you is to run a test, assuming you have the tech in place to analyse the outcome.
Looking Ahead: The Future of Privacy Sandbox and Topics
It’s good to remember that the amount of Topics-included inventory for Prebid partners is currently limited. So even if you activate Topics, it does not mean these will be available for your Prebid partners in every call. The reason for this relates to the details of how Topics mimics the logic of 3rd-party cookie sync, and the reason for this behaviour is privacy. It's all explained well in the Privacy Sandbox documentation, so feel free to dive deeper. The outcome of this behaviour is that as more Prebid publishers activate Topics, the number of opportunities to use Topics signals for SSPs will increase.
Based on our talks with the ad tech community, it seems that buy-side tech will continue to implement Privacy Sandbox solutions despite the news about the hard deadline for Chrome 3rd-party cookies being erased. But we all know that in the bigger picture, nothing changes: the erosion of 3rd-party cookies will inevitably continue.
This post was a high-level summary of our current findings. Please do not hesitate to contact us if you'd like to hear more about the details and hard numbers.