The objective of the study is to evaluate the effectiveness of a HIV risk assessment tool to promote HIV testing and to reduce high risk sexual behaviors among men who have sex with men (MSM). It hypothesizes that the social media-based HIV risk assessment tool can increase 20% HIV testing proportion during the six months follow-up period.

Inclusion Criteria:

• Male at birth.
• Having had homo-sexual behaviors (anal/oral) in the past 6 months before enrollment.
• An age of 18 years or older.
• Living in Beijing, China.
• Self-reporting HIV negative or unknown.
• Willingly participating into the baseline survey and the six months follow ups.
• Agreeing not to share the research link to others.
• Owning a mobile phone and having had downloaded the social networking Application Blued before enrollment.

Exclusion Criteria:

• Not accepting blood sampling within the study period.
• Reporting injecting drugs use in the past six months before enrollment.
• Being currently involved in other HIV behavioral interventions for MSM.
• Having a specific plan to leave from Beijing in the next 6 months.
• Self-reporting female.
• Other reasons the investigators deem make participation either detrimental to the participants or the study.