Russian operatives set up an array of misleading Web sites and social media pages to identify American voters susceptible to propaganda, then used a powerful Facebook tool to repeatedly send them messages designed to influence their political behavior, say people familiar with the investigation into foreign meddling in the U.S. election.
The tactic resembles what American businesses and political campaigns have been doing in recent years to deliver messages to potentially interested people online. The Russians exploited this system by creating English-language sites and Facebook pages that closely mimicked those created by U.S. political activists.