Pay per click (PPC) advertising over the past few years has gained importance and companies invest larger amounts of money into it. There are more PPC systems in the market from which to choose for advertising. Which PPC system is appropriate to use for a specific campaign? This thesis consists of four chapters (excluding introduction and conclusion). The first chapter clarifies terms, talks about the basic characteristics of the subject and gives an idea of the importance of the topic (position of pay per click in the market of internet advertising). The second chapter characterizes three PPC systems (and their principles) which the author considers to be the most important in the Slovak market. The third chapter is important for the chara...