Unique on Facebook: Formulation and evidence of (nano)targeting individual users with non-PII data

Jose Gonzalez-Cabañas, Angel Cuevas, Ruben Cuevas, Juan Lopez-Fernandez, David Garcia

Research output: Chapter in Book/Report/Conference proceedingConference paperpeer-review


The privacy of an individual is bounded by the ability of a third party to reveal their identity. Certain data items such as a passport ID or a mobile phone number may be used to uniquely identify a person. These are referred to as Personal Identifiable Information (PII) items. Previous literature has also reported that, in datasets including millions of users, a combination of several non-PII items (which alone are not enough to identify an individual) can uniquely identify an individual within the dataset. In this paper, we define a data-driven model to quantify the number of interests from a user that make them unique on Facebook. To the best of our knowledge, this represents the first study of individuals' uniqueness at the world population scale. Besides, users' interests are actionable non-PII items that can be used to define ad campaigns and deliver tailored ads to Facebook users. We run an experiment through 21 Facebook ad campaigns that target three of the authors of this paper to prove that, if an advertiser knows enough interests from a user, the Facebook Advertising Platform can be systematically exploited to deliver ads exclusively to a specific user. We refer to this practice as nanotargeting. Finally, we discuss the harmful risks associated with nanotargeting such as psychological persuasion, user manipulation, or blackmailing, and provide easily implementable countermeasures to preclude attacks based on nanotargeting campaigns on Facebook.

Original languageEnglish
Title of host publicationIMC 2021 - Proceedings of the 2021 ACM Internet Measurement Conference
PublisherAssociation of Computing Machinery
Number of pages16
ISBN (Electronic)9781450391290
Publication statusPublished - 2 Nov 2021
Event21st ACM Internet Measurement Conference: IMC 2021 - Virtuell, United States
Duration: 2 Nov 20214 Nov 2021


Conference21st ACM Internet Measurement Conference
Abbreviated titleIMC 2021
Country/TerritoryUnited States

ASJC Scopus subject areas

  • Software
  • Computer Networks and Communications


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