In the SS4SH pilot study, utilizing a data-driven approach in partnership with the local health department, the investigators analyzed local public health surveillance data to identify online sex partner meeting spaces frequently reported by (majority Black) MSM newly diagnosed with HIV and/or syphilis. The identified online spaces were used to advertise mobile van HIV/STI testing for MSM \> 18 years of age and less than 49 years of age over a 14-month period. The strategy and advertisements were informed by a community advisory board (CAB) of MSM hosted at a local Lesbian, Gay, Bisexual, Transgender, and Queer (LGBTQ) community-based organization to ensure local relevance, acceptability and feasibility.