Eyeo's Sensible Privacy Enablement by Clustering Targeting Attributes in CLiEnt (Spectacle) is a proposal to allow marketers only a subset of audience segments for any ad decision. Eyeo's Spectacle proposal will make available only a subset of current audience segments on any given ad request.
Eyeo is the company that operates AdBlock Plus, which allows companies to accelerate being whitelisted from default blocking via a payment.
In addition to the total quantity of audiences available, Eyeo's proposal limits which individual audience segments are eligible for being made available by exceeding some minimum distinct count threshold. To measure this distinct count Eyeo recommends using differential privacy, where different servers receive different subsets of information and by combing their partial results the true answer can be approximated. Eyeo recognizes this system has issues, as web "clients sometimes report incorrect membership to the server, indicating membership to segments that they are not members of, and non-membership to segments in which they are actual members."
Spectacle concisely lists many core marketer use cases that any viable proposal must satisfy as well as issues with other Privacy Sandbox proposals:
- Audience Generation
- Authentication: "Offloading trust of the client to sign in systems (Google, Apple, Facebook, etc.) allows a separate registration system to manage identity and increase the cost of performing fraud. However, required registration forces the user to become known, breaking the fundamental premise of anonymity."
- Sequential messaging: "This includes delivering a series of ads that tell a coherent story, and capping the number of times a specific ID is permitted to see the same ad."
- Frequency capping: Setting a maximum number of times an ad can be delivered to a specific user is a key feature that minimizes unnecessary spend while also improving user experience."
- Independent audit: Reducing independent auditing "impacts the ability of measurement systems to validate the metrics reported by the systems allowed to deliver ads."
- Fraud detection: "When segment membership is created within the client, and the client is hardened against oversight by third parties, it is easy for a client to lie to the advertising systems about actual segment membership."
- Attribution: "Being able to understand what exposures led to a specific outcome is the goal of attribution.... However, trusting the client to do attribution provides a great opportunity for manipulation by bad actors."
- Real-time feedback: Absence of accurate feedback negatively impacts software designed "to tune campaigns during execution, as well as other measurement systems."
Spectacle criticizes many of the Privacy Sandbox proposals that centralize more data collection within internet gatekeepers:
- VPN or Full Proxy
- "A VPN aims to pass all network traffic through a new IP address without otherwise modifying it. This has more operational overhead and might exceed the scope of a product aiming at delivering better, more private ad experiences. A full proxy sends all web traffic through the product owner’s servers. This allows the product provider to observe all web activity—a privacy risk for the user."
- Email Rely Proxy
- Eyeo notes that internet gatekeepers are similarly offering per-publisher email alias that route via an Email Rely Proxy to an individual's actual inbox, which is vulnerable to the same concerns.
Eyeo is to be commended for concisely listing a set of marketer use cases required for them to continue advertising across Open Web publishers. If such advertising effectiveness is significantly impaired, publishers and people will suffer. "Advertising remains the best method of supporting the free web and allowing content and services to be widely available for all types of users. Without ad funding, access to content and services on the web would be a costly service that only few can afford."
Eyeo also makes repeated mention of the importance of not impairing people's web experiences.
Eyeo notes that a solution must not only be scaled but useful. "An advertising profile is only of value if it can be used as input into ad decisioning.... The product needs to have a sufficiently large install base to be attractive to buyers."
The minimum audience segment size has the same issues as FLoC in discriminating against smaller players.
Eyeo does not describe how marketers are meant to conduct media planning use cases that currently rely on forecasting techniques to help allocate budgets to particular audiences in context.
- How frequently can audience memberships be changed?
- What is the impaired value based on the subset of otherwise eligible audiences being made available?
- What is the impact to publisher yield or marketer buying systems' ability to work with multiple clients if the larger the install base the greater the array of eligible audiences received which Eyeo believes to be analogous to a statistical ID?