How have personal ads changed in the last 30 years, and how has the HIV/AIDS crisis influenced these changes? We analyzed 250,000 personal ads for men who have sex with men from the online classifieds website Craigslist.org and found that the percentage of ads using sexual health-related language have increased from 23% in 1988 to 53% today. Analysis also showed that use of sexual health-related language in a location correlates with HIV prevalence rates.