Over the past decades, the quantity of data has increased exponentially and currently represents both a risk and an opportunity for companies. On the one hand, the growing amount of information about customers has enabled firms to lead personalised marketing actions. On the other hand, storing safely data about customers is a new and dangerous issue. Indeed, several important leaks have already occurred. These latter have seriously damaged the public image of the concerned companies. This thesis will therefore analyse this duality between risks and opportunities in relation with the development of Big Data. This paper will also explore the ethical aspect of Big Data, a concern that has arisen more recently. More and more users of digital devices care about the personal information that companies might use to inflate their profit. In parallel to theses ethical concerns, new possibilities keep blossoming and Big Data seems to have a bright future ahead of it.