This bachelor's thesis is focused on online marketing, more specifically on advertising through PPC systems. It introduces the two most widely used tools for this form of advertising in the Czech Republic. It also describes the principles of the functioning of these systems, the process of preparation of advertising campaigns, optimization and evaluation. The main goal of this thesis is to evaluate the advertising campaigns from the above mentioned systems, to compare them and to submit a proposal for improving the efficiency to the next period. Other tools, such as Google Analytics, keyword planners, web site monitoring tools, etc., will be used to meet the goals. The main contribution of this work include a more effective appreciation of ...