Techniques and infrastructure are provided for supporting global customization. The invention enables persona profiles of user information to be maintained, and such persona profiles to be accessed by merchants. Via the persona abstraction, users control what information is grouped into a persona profile, and can selectively enable a merchant to read one of these profiles. The infrastructure of the invention employs a persona server that assists users in managing their personae. The infrastructure of the invention separates this from the profile databases at which persona profile information is stored, to eliminate any single point at which different persona profiles can be tied to the same user. Since merchants also have privacy concerns, the infrastructure of the invention provides a data protection model based on tainting, by which merchants can limit how the information they contribute can be exposed.