Diversity in knowledge production is a core challenge facing science communication. Despite extensive works showing how diversity has been undermined in science communication, little is known about to what extent social media augments or hinders diversity for science communication. This article addresses this gap by examining the profile and network diversities of knowledge producers on a popular social media platform—YouTube. We revealed the pattern of the juxtaposition of inclusiveness and segregation in this digital platform, which we define as “segregated inclusion.” We found that diverse profiles are presented in digital knowledge production. However, the network among these knowledge producers reveals the rich-get-richer effect. At the intersection of profile and network diversities, we found a decrease in the overall profile diversity when we moved toward the center of the core producers. This segregated inclusion phenomenon questions how inequalities in science communication are replicated and amplified in relation to digital platforms.