SAN FRANCISCO • Public databases that shine a light on online political ads - launched by Facebook and Google before Tuesday's US elections - offer the public the first broad view of how quickly the companies yank advertisements that break their rules.
The databases also provided campaigns with unprecedented insight into opponents' online marketing, enabling them to capitalise on weaknesses, political strategists told Reuters.
Facebook Inc and Google, owned by Alphabet Inc, introduced the databases this year to give details on some political ads bought on their services, a response to US prosecutors' allegations that Russian agents who deceptively interfered in the 2016 election purchased ads from the companies.
Russia denies the charges. US security experts said the Russians changed tactics this year.
Reuters found that 436 ads - 375 on Facebook and 61 on Google - from May to last month related to 34 US House of Representatives contests that were declared competitive last month by RealClearPolitics, which tracks political opinion polls.
Of the 258 removed ads with start and end dates, data from the databases collected by Reuters showed that the ads stayed on Google for an average of eight days and Facebook for 15 days.
Based on ranges in the databases, the 436 ads were displayed up to 20.5 million times and cost up to US$582,000 (S$797,000), amounting to a fraction of the millions of dollars spent online in those races.
Google said it is committed to bringing greater transparency to political ads. Facebook said the database is a way the company is held accountable, "even if it means our mistakes are on display". In some cases, the companies' automated scans did not identify banned material, such as hateful speech or images of poor quality before ads went live.
Google's database covers US$54 million in spending by US campaigns since May and Facebook's covers US$354 million, showed the databases. Facebook's figure is larger partly because its database includes ads not only for federal races but also for state contests, national issues and get-out-the-vote efforts.
Five campaign strategists told Reuters they adjusted ad tactics in recent weeks based on what the databases revealed about opponents' ad spending and which genders, age groups and states saw the messages.
Mr Ryan Morgan, whose consulting firm Veracity Media arranged attack ads for a US House race in Iowa, said his team tripled its online ad budget to US$600,000 for a San Francisco affordable housing tax after Facebook's database showed the other side's ads were reaching non-Californians. That intelligence "let us know that digital was a place we could run up the score".