Risks of homophily

Social network services provide us with options for choosing an online space where we want to be involved. For instance, a popular online community, Reddit, has tons of subReddits (e.g., teachers, mathematicians, carpenters, Tesla car owners, and so on). Of course, users can join the subReddit they are interested in and are actively participating in the Subreddits. This is very natural since we, as human beings, feel comfortable when we experience/interact with similar things we have already experienced. We tend to associate and bond with others who/which are similar to us/experiences, and this mutual attraction due to similarity is called "homophily." In online spaces, however, this homophily could disadvantage students in learning. Confirmation bias in information gathering might be one of the risks of homophily. Can we guarantee the information we are gathering on a particular online space is validated enough?