•YBMSM were more likely to belong to personal/professional development groups.•YBMSM clustered around pairs of LGBTQ identity, sex, and nightlife groups.•Regular testers tended to belong to LGBTQ identity and nightlife groups.•Those who engaged in condomless sex tended to affiliate with LGBTQ identity groups.•Those who were aware of PrEP aware tended to affiliate with chat groups.
© 2019 The Authors.