How to give internet users control back about their online data ?

This thesis, made in my last year of Master's degree in Paris (at école Estienne), try to give an answer to this question, investigating online surveillance and data business topics.

The first part tries to define the new issues related to personnal data and our new relationship with online privacy. The second part focuses on Big Data : how our datas are collected, analyzed, and selled by private corporations ; it seems that data have become the oil of the 21st century. Finally, this thesis introduces existing alternatives to "bypass" hidden networks and data marketplaces through an overview of open-source, makers and hacking movements.