To become one of the dominant digital advertising platforms, Facebook used the data of its members to create hyper-specific categories so marketers could get close to their most valued customers.
That same targeting technology presented a gold mine for Russians over the past five years in their efforts to influence American voters.
In a report created for the Senate Intelligence Committee and provided to CNBC on Monday, researchers analyzed Russia's use of online propaganda to spread false information and polarize U.S. voters between 2013 and 2018. Russia's Internet Research Agency (IRA) reached tens of millions of users in the U.S. on social media, including more than 30 million users who shared IRA-created Facebook and Instagram posts with their circles.
"Indeed, this effective impression management—and fine-grained control over who receives which messages—is what makes social media platforms so attractive to advertisers, but also to political and foreign operatives," the researchers wrote in the report.
More than $1 out of ever $5 spent on online ads will go to Facebook in 2018, according to eMarketer, and the platform is second to Google in the digital advertising market. Advertisers want to be very specific when they show ads to people online because they have to weed through so much content.
Facebook lets advertisers reach a target audience based on user behavior and characteristics like someone who's married, lives in a certain area and has particular interests. Marketers can also upload lists of emails or individual Facebook IDs to reach specific people, a useful technique for retailers who want to contact existing customers.
While these tools can make marketing more effective, they can also be abused. A ProPublica report in November 2017 showed that advertisers could buy housing ads that excluded specific races and ethnic groups, which is illegal. Marketers could also discriminate with job ads, excluding certain ages and races.
The IRA's content used very similar tactics to divide U.S. voters and interfere with elections. For example, it focused on getting African-Americans to boycott voting or gave them wrong information on voting procedures. There were also campaigns aimed at Mexican-American and Hispanic voters, with the intent of spreading distrust about U.S. organizations, and messages to encourage extreme right-wing voters to be more confrontational.
The report to lawmakers on Monday made clear that the activity did not stop after the IRA's attempt to sway the 2016 election was made public.
Facebook has spent all of 2018 reckoning with the consequences of platform abuse, most notably the Cambridge Analytica scandal, which involved the improper collection of user data. Facebook has since cracked down on third-party data providers.