Increasingly, public libraries are incorporating interactive, collaborative, and user-centred social discovery tools into traditional library services with the goal of better serving their patrons. These tools are designed to encourage communication and interaction between library patrons and staff by providing a platform for patrons to evaluate, comment on, create, and share personalized lists of their favourite items in a library’s collection. BiblioCommons is one example of a discovery tool that has been embraced by public libraries and their patrons to this end. Yet, while tools such as BiblioCommons offer many benefits to library patrons, relying on these tools to deliver core library services may violate patron privacy and confidentiality. Using the American Library Association Code of Ethics and the Library Bill of Rights as a framework, we explore the websites of Canadian public libraries that use BiblioCommons to discover how these libraries communicate privacy concerns associated with the use of this service to their patrons. Based on our findings, we argue that libraries are largely failing in their ethical responsibility to alert patrons to the privacy and confidentiality concerns associated with BiblioCommons.