The Net Gay Barometer (NGB) is a periodic online survey, launched in 2004 and updated in 2009, conducted among men who have sex with men (MSM) recruited through French gay dating sites. A total of 24,292 MSM responded to the online questionnaire, of whom 3,003 (17%) were aged 18 to 25. Compared to their older counterparts, these young men were more likely to have attended college, were more likely to live in rural areas, and were less likely to identify as gay. Their self-reported HIV prevalence was 2.5%. Less frequent visitors to sexual encounter venues than their older counterparts, they reported having fewer casual partners with whom they were less often engaged in “regular” risk-taking behaviors. However, 62% reported not always using protection with their steady partner, while more than a quarter were in “open” relationships and 36.4% reported unprotected anal intercourse with a serodiscordant or serostatus-unknown partner. Thanks to the Internet, the NBG was able to collect a significant number of questionnaires from young MSM, which can be used to implement targeted prevention programs tailored to this specific group. (R.A.)