This study examines the perception on third-party tracking of German Internet users. For that purpose, 20 users without a technical background were interviewed. Results indicate that users are not aware of online tracking. They are often surprised by the magnitude of tracking programs they are exposed to during everyday life online activities like travel planning, job or product research. While the interviewees were willing to concede the theoretical advantages of such data collection, e.g. for behavioral targeting, they considered the price as too high to compensate for the loss of privacy control. The participants showed concerns that tracking could possibly lead to disadvantages in real life. In addition, behavioral targeting is assessed fairly redundant. Asked about concepts for enhanced transparency and control, the interviewed people still emphasized their distrust toward tracking. Thus, third-party tracking is a doubled edged sword for online advertising. On the one hand, it is a central means to improve the relevancy of the often unwanted display ads. At the same time, there is a great danger of increasing ad aversion for privacy reasons.