The internet is not only a medium for free personal expression and limitless creativity but also a place where different interests collide. In regulating these interests, fundamental rights can play an important role as guiding principles. This applies primarily to attempts at surveillance by state authorities, such as online searches or the systematic evaluation of communication circumstances, which have recently been the subject of several decisions by the Federal Constitutional Court. Additionally, the practice of creating and marketing personality profiles of users by internet companies like Facebook or Google is also under scrutiny. The work examines, in the first part, the effectiveness of individual fundamental rights guarantees as defensive rights, but also as a means of establishing state regulations.