Under what conditions can the written, visual, or audio traces of online activities be used as research data without the consent of the individuals who produced them? This question, central to discussions about online research ethics, has been addressed by norm-setting bodies from the perspective of privacy. Yet the transposition of the private/public distinction to digital contexts raises several issues, mostly resulting from conceptual confusion. Attempting to clear this confusion, this article proposes five clarifications concerning the public or private status of digital traces with regard to their accessibility; the awareness of this accessibility by the people who generate these traces; the distinction between private and intimate; the links between content visibility and publicity, and the way in which publicity can be amplified by research.