As the frequency of internet-based research has increased, it is important for researchers to consider how the conditions in which data are collected may influence the risks to participants. In particular, because internet-based data collection often occurs outside a clinical or research setting, there may be unintentional disclosures of a participant's involvement in a research study of which the researcher is unaware. The current analysis examined the responses of men who have sex with men participating in an internet-based HIV behavioural risk study when queried about the possible disclosure of their participation in the study. Fewer than 2% of participants indicated that their participation in the research study was disclosed, and all but one indicated no negative outcomes associated with the disclosure. As the field of online research continues to expand, it is important to consider risks that are unique to internet-based research, and to monitor these risks to ensure that the confidentiality of research subjects is maintained.