Social networking sites (SNS) such as Facebook have created a new way for individuals to share personal data and interact with each other on the Internet. The disclosure of this personal data is directly tied to the existing relationships of individuals within an SNS. Individual privacy settings allow a selective disclosure of personal data to specific connected individuals. In this paper, we present first empirical insights of a grounded theory study, based on 37 qualitative interviews with Facebook users, which reveal factors that drive, or generally influence, the use of these individual privacy settings on SNS. By investigating this privacy protection behaviour towards connected individuals, so-called friends in Facebook's terminology, we add new perspectives to existing theories of information privacy protection 'individuals' privacy protection behaviour in non-anonymous online environments. We have developed a conceptual model showing that the motivation to use individual privacy settings depends on a complex interplay between different factors. As important drivers, motives for using SNS, existing relationships and context of personal data disclosure have been identified. Building on those insights further allows development or improvement of general privacy controls for individuals interacting with each other on the Internet.