As the online learning landscape expands and social media continue to be an important information source for many, it is important to ask how people evaluate and experience online sources of learning differently and how this compares across domains. Drawing on interviews with 45 adults in the United States, we examine how people’s attitudes and experiences around online learning differ across science and religion. We find that the topic shapes how people evaluate different ways of seeking knowledge online, including through social media. Trust, knowledge, ease, and privacy further influence how people approach learning by domain. Our findings highlight incidental learning through online social networks, suggesting that personal (offline and online) networks as well as intentions shape how the internet helps people learn. We discuss the implications of the findings for future research on the online learning landscape considering the different experiences people have when learning about different topics.