In his thesis, Markus Göckeritz investigates the "Majority Illusion” which was introduced by Lerman et al. (2015). When individuals can not observe the entire network, they form opinions by observing their social neighborhood. Often the distribution in a neighborhood is skewed by few, very influential individuals. The structure of social networks amplifies the influence of highly connected individuals and can cause their opinions and behavior, while globally rare, to be perceived as common or predominant by all participants in the network. This illusion is caused by the structure of social networks and occurs naturally in real world networks. Markus Göckeritz implemented a distributed algorithm to quantify this phenomenon and he presents a new and efficient method that exploits this effect to find a small set of individuals that, if persuaded to change their views, would cause a global cascade of opinion changes. This can be used to cause or prevent such changes. Traditionally, applications for these methods can be found for marketing and advertisement. In light of recent global trends this topic has become very relevant for social and political activism and the news media.