Through the development of technology and the Internet, we have witnessed increased accessibility and popularization of various social networking sites which have inevitably entered our lives and have also become a part of our everyday life. This master's thesis presents research done in social media and the analysis of the same, with a specific reference to Facebook, as one of the most popular social media sites today. Facebook has been constantly growing over time and today has more than 1.550,000,000 active users. In recent years, through massive expansion and integration with other social media sites such as Instagram or YouTube, it has become one of the most important platforms for social, private, but also business communication. Business relationships with other companies, client relationships, all kinds of social interaction as well as a substantial amount of information prove that Facebook has become so much more than it was initially intended by its founder. By way of detailed analysis and examples we will try to research the phenomenon of Facebook and the fact that still, thirteen years after it was founded, it is the most popular social media site. We will also present all sorts of communication that can be found on it.