The processing of personal data in numerous Web 2.0 platforms, mostly willingly divulged by users as well as the legal impacts on European level and especially in Austria were decisive for the choice of my topic. This paper aims to demonstrate legal and social impacts when losing control over personal information of private persons. As already enshrined in the title of my master thesis, the time period for my research starts at the era of Big Brother in the 1970-s up to now, which is called the era of Big Data. The first two chapters include all definitions, which form the basis of my research. To understand the development and features of Big Data, these chapters include definitions of privacy, data protection and personal data. My thesis also covers the development of society in conjunction with the enactment of applicable Austrian laws, as well as regulations and directives of the European Union concerning data protection of personal information. Besides that, the existing data protection mechanisms and approaches are taken into account. In this context the Austrian Data Protection Act is an important source of information. However, since these legal conditions are partially outdated, I pointed out obsolete and insufficient parts. Furthermore, I paid particular attention to personal data used in cloud computing, web-tracking, video surveillance and Big Data. In order to establish a connection to the real life examples, I also concentrated on "Hot topics". Finally, I published my research results in a blog, to open the social development and the current legal situation in a clear and understandable way to the public.