Social networking technologies are influential among men who have sex with men (MSM) and may be an important strategy for HIV prevention. We conducted focus groups with HIV positive and negative participants. Almost all participants used social networking sites to meet new friends and sexual partners. The main obstacle to effective HIV prevention campaigns in social networking platforms was stigmatization based on homosexuality as well as HIV status. Persistent stigma associated with HIV status and disclosure was cited as a top reason for avoiding HIV-related conversations while meeting new partners using social technologies. Further, social networking sites have different social etiquettes and rules that may increase HIV risk by discouraging HIV status disclosure. Overall, successful interventions for MSM using social networking technologies must consider aspects of privacy, stigma, and social norms in order to enact HIV reduction among MSM.