What kinds of information and alerts might cause internet users to be more cautious about what they reveal online? We used a 25-item survey to determine whether the strength of Terms of Service (TOS) warnings and the inclusion of a click requirement affect people's willingness to admit to engaging in inappropriate behaviors. A racially and ethnically diverse group of 1,500 people participated in the study; 98.3% were from the US and India and the remainder from 18 other countries. Participants were randomly assigned to five different groups in which warnings and click requirements varied. In the control condition, no warning was provided. In the four experimental groups, two factors were varied in a 2 × 2 factorial design: strength of warning and click requirement. We found that strong warnings were more effective than weak warnings in decreasing personal disclosures and that click requirements added to the deterrent power of both strong and weak warnings. We also found that a commonly used TOS warning has no impact on disclosures. Participants in the control group provided 32.8% more information than participants in the two click requirement groups combined and 24.3% more information than participants in the four experimental groups combined. The pattern according to which people dropped out of the five different groups sheds further light on the surprising power of the click requirement, as well as on the importance of tracking attrition in online studies.