We present the results of a study of information sharing behaviour of the users of a personal learning space. Our study uses grounded theory methodology and involves 12 K12 students who have used a personal learning space for over a year. The resulting grounded theory suggests that users' preferences regarding privacy of their artefacts in such an environment depends on a number of factors, including the current stage in the artefact's life cycle, the nature of trust between the owner and the receiver of information, and the dynamics of the group or community within which the information is being shared. Based on our findings, we propose a framework for understanding and designing privacy control mechanisms for personal learning spaces that reflect users' mental model of information privacy. To illustrate these principles in practice, we describe the privacy management mechanisms of OpnTag, an application we have designed as a test bed for social information management.