"This chapter critically discusses how the democratic arena is changing and deteriorating due to the impact of the power of social media platforms. The focus is on the consequences that personalized forms of information and digital affordances can produce, leading to online information cocoons or filter bubbles that limit the range of political ideas that people can encounter. Then, the threats to democracy and liberty produced by closed online spaces in which people of similar opinions can congregate are discussed. Finally, the chapter analyses an approach to the regulation of social media based on assessing the nature of digital capitalism and how we pay for the digital services offered by social media platforms." (Abstract)