Bibliometric analysis has a long tradition in the context of scientific communication (Hood and Wilson 2001). In current discussions related to the impact of research results one can observe a more economically driven perception of bibliometric and scientometric indicators. Therefore the statistical methods and the conceptual framework involved must be understood and interpreted adequately. This contribution illustrates various uses of the impact factor, being provided by Thomson ISI as well as by other organisations. Web-based information services enhance the applications of citation patterns for relevance ranking. 471