Researchers show Facebook’s ad tools can target a single user - TechCrunch

^{( October 15, 2021; TechCrunch )}

“The main conclusions derived from our experiment are the following: (i) nanotargeting a user on FB is highly likely if an attacker can infer 18+ interests from the targeted user; (ii) nanotargeting is extremely cheap, and (iii) based on our experiments, 2/3 of the nanotargeted ads are expected to be delivered to the targeted user in less than 7 effective campaign hours,” they add in a summary of the results.

In another section of the paper discussing countermeasures to prevent nanotargeting, the researchers argue that Facebook’s claimed limits on audience size “have been proven to be completely ineffective” — and assert that the tech giant’s limit of 20 is “not currently being applied”.

With the 4 rarest interests or 18 random interests, the researchers claim they can target an individual user with better than 90% confidence.

According to the paper, this sort of nanotargeting puts individuals at risk of "psychological persuasion, user manipulation, or blackmailing". Using a real-world example from 2017, when Jeremy Corbyn was targeted along with some journalists and other influencers, the article also reveals that this sort of manipulation can have sweeping impacts.

The article doesn't discuss this, but it also occurs to me that multiple ad campaigns could probably be used by an advertiser to create interest profiles of the FB users who react to the sponsored posts, and these profiles could then be utilized for subsequent nanotargeting.

Read the rest from TechCrunch: Researchers show Facebook’s ad tools can target a single user

References:

• Unique on Facebook: Formulation and Evidence of (Nano)targeting Individual Users with non-PII Data - ( October, 2021; arXiv )
• FDVT: Data Valuation Tool for Facebook Users - ( May, 20217; ACM CHI Conference )