In 1890 Samuel Warren and Louis Brandeis published a groundbreaking article in the Harvard Law Review arguing that privacy protections are part of a “right to be let alone.” The article strongly influenced theories of privacy over subsequent decades, and has been referenced in important U.S. Supreme Court rulings. But since the 19th century, society has changed in profound ways. We now interact daily with technologies that closely track our communications and behavior, collecting personal data for targeted advertising, trade among data brokerages, and mining by governments for criminal and political investigations. More than ever, the right to be let alone would appear to be under siege. In this paper I present two prominent critiques of the Warren/Brandeis conception of the right to privacy, so as to begin addressing the inadequacies of privacy protections in today’s world of ubiquitous digital information. Richard A. Posner views privacy as a question of economics and market efficiency. He rejects the conception of privacy as “the right to be let alone,” and suggests that individual privacy has little economic value to society, in contrast to commercial privacy which can have great value in a capitalistic market-based economy. Daniel Solove offers a theory of privacy based on Ludwig Wittgenstein’s notion of family resemblances, accounting for the contextual value of privacy based on prevailing social practices and norms. I wrote this short article for an assignment in a doctoral class on the history and foundations of information science. Given the assignment parameters, the article represents only a few points on the spectrum of conceptions about privacy. I was unable to include the important theoretical work of many other scholars whose work is essential to understanding privacy in the digital age. In particular, Helen Nissenbaum's articulation of the "contextual integrity" of privacy is laying important groundwork for new conceptions of privacy protection. Julie E. Cohen calls for recognition of the social harms increasingly evident in the "biopolitical domain," a space where personal information is acquired and exploited as raw materials for various types of marketplace activities. Oscar H. Gandy, Jr. identifies the inherent power imbalances of the "panoptic sort," and offers a theoretical framework for social and policy interventions. These and other important contributions are not covered here, but will be elsewhere as my research continues.