Social media have been firmly entrenched in the modern eve-ryday life. Still, their influence on the formation of public opinion is not well understood. An important feature of social media is that they are not neutral. Not only do people interact with each other on social media platforms, but social media themselves actively interact with people, selecting personalized content for them based on the information about their interests and behavior. In 2011, Eli Pariser hypothesized that content personalization should lead to the formation of a kind of "information cocoons", or "filter bubbles" - ho-mogeneous groups of users who hold similar views. However, the fragmen-tation of the Internet community into "filter bubbles" is not the only threat posed by the use of personalization algorithms. Even more dangerously, social media possess the ability to manipulate content selection algorithms in order to influence users' views.