The ubiquity of social media platforms fuels heated discussions about algorithms and selection biases leading people into online “echo chambers.” Scholars argue that social media deepen societal polarization and fuel political extremism. However, studies often focus on media effects, disregarding individual agency and (sub)cultural values that shape communication. As a strategic case study, this article, based on a mixed-methods analysis, including a social network and qualitative analysis of 1199 comments under four conspiracy theory comment sections on YouTube, questions how insular these spaces are? And how people in these networks communicate? We find that the discussions in our strategically sampled comments sections lie between homogeneous closed debates and open debates. In other words, the networks in our sample vary in their “echo chamberness.” Based on our findings, we contend that variations in the echo chamberness of the various comment sections can be explained via the lens of conspiratorial (sub)cultures.