FLoC is an automatic ad targeting method without cookies from Google that "protects privacy" by providing Internet users with a greater degree of anonymity than the third-party cookie.
However, FLoC could make it faster and easier for advertising companies to identify and access information about people online, as various data privacy and ethics advocates have anticipated, companies are beginning to combine FLoC credentials with existing identifiable profile information.
Tech companies operating in the digital identity management market say the identifiers will help improve the accuracy of systems that detect people's identities and could even serve as persistent identifiers.
"The more signals we have, the more accurate we will be, and the FLoC identifiers will be one of the signals we will use," said Mathieu Roche, CEO of ID5.
Google designates FLoC as a privacy-friendly ad targeting model because the method doesn't track people individually. Instead, FLoC uses machine learning to group people based on the web pages they have visited.
Additionally, the FLoC ID assigned to people is updated weekly, which is intended to filter them into gradually evolving collectives and apparently limit the use of a FLoC ID as a persistent identifier. Since the system works automatically in web browsers like Chrome, Google doesn't precisely define how it assembles the cohorts.
However, the advertising industry (which has adopted fundamental internet technologies such as the cookie and the IP address to identify people online) sees an opportunity to do the same with FLoC IDs hoping to prevent the imminent disappearance of cookies.
Over time, FLoC identifiers could function as persistent identifiers in the same way as IP addresses, said Nishant Desai, director of technology and group operations at Xaxis, the adtech arm of GroupM.
Like IP addresses, FLoC IDs will not be completely static. However, the same FLoC IDs or the same ID range are likely associated with someone.
"If his behavior doesn't change, the algorithm will continue to affect him in that same cohort, so some users will have a persistent FLoC ID associated with them, or could have one."
Privacy advocates have argued that FLoC credentials can alleviate the difficulty for companies to collect information about an individual.
While up to now a web user should have visited a website at least once before the site can place a cookie on their machine to track their movements on the web, a FLoC ID and the signals it emits will be known.
In addition to connecting FLoC identifiers to other types of data, Google's cookieless targeting method can be used on its own to create audience profiles.
However, it is clear that other companies view FLoC credentials as potentially valuable identity data, which is why privacy advocates like Cyphers view them as a privacy concern, which is not as theoretical.
Chrome will assign a FLoC ID to each Chrome user who has not unsubscribed, disabling the browser's privacy sandbox setting or blocking it with an extension. So even if someone has never visited a site before, the FLoC ID can reveal information about that person that the site or the ad system might not otherwise have.
For example, together, these data cues could reveal a person's gender, if they are likely to be in an income bracket above or below a certain income, or if they live in a certain region.