The author investigates issues faced by academic research libraries in providing virtual reference services to unaffiliated users. These libraries generally welcome visitors who use on-site collections and reference services, but are these altruistic policies feasible in a virtual environment? This paper reviews the use of virtual reference service by unaffiliated users to determine their expectations, assess level of demand, and provide recommendations on how libraries should respond. Virtual reference desks can serve their primary constituency and function as a public good for external users if they understand and articulate their role as mediators in the information seeking process.