The paper explores the impact of social media platforms on the formation of echo chambers, focusing on how different interaction paradigms and feed algorithms influence information spreading. The authors analyze over 100 million pieces of content from Gab, Facebook, Reddit, and Twitter, covering controversial topics such as gun control, vaccination, and abortion. They quantify echo chambers using two main metrics: homophily in interaction networks and bias in information diffusion toward like-minded peers. The results show that homophilic clusters dominate online interactions on Facebook and Twitter, leading to higher segregation on Facebook compared to Reddit. The study highlights the significant differences in echo chamber dynamics across platforms, emphasizing the role of feed algorithms and user interaction paradigms in shaping information consumption and public opinion.The paper explores the impact of social media platforms on the formation of echo chambers, focusing on how different interaction paradigms and feed algorithms influence information spreading. The authors analyze over 100 million pieces of content from Gab, Facebook, Reddit, and Twitter, covering controversial topics such as gun control, vaccination, and abortion. They quantify echo chambers using two main metrics: homophily in interaction networks and bias in information diffusion toward like-minded peers. The results show that homophilic clusters dominate online interactions on Facebook and Twitter, leading to higher segregation on Facebook compared to Reddit. The study highlights the significant differences in echo chamber dynamics across platforms, emphasizing the role of feed algorithms and user interaction paradigms in shaping information consumption and public opinion.