The problems of corporate concentration and privacy on the Internet are inextricably linked. A new regime of interoperability can revitalize competition in the space, encourage innovation, and give users more agency over their data; it may also create new risks to user privacy and data security. This paper considers those risks and argues that they are outweighed by the benefits. New interoperability, done correctly, will not just foster competition, it can be a net benefit for user privacy rights.