Social bookmarking systems constitute an establishedpart of the Web 2.0. In such systemsusers describe bookmarks by keywordscalled tags. The structure behind these socialsystems, called folksonomies, can be viewedas a tripartite hypergraph of user, tag and resourcenodes. This underlying network showsspecific structural properties that explain itsgrowth and the possibility of serendipitousexploration.Today’s search engines represent the gatewayto retrieve information from the World WideWeb. Short queries typically consisting oftwo to three words describe a user’s informationneed. In response to the displayedresults of the search engine, users click onthe links of the result page as they expectthe answer to be of relevance.This clickdata can be represented as a folksonomyin which queries are descriptions ofclicked URLs. The resulting network structure,which we will term logsonomy is verysimilar to the one of folksonomies. In orderto find out about its properties, we analyzethe topological characteristics of the tripartitehypergraph of queries, users and bookmarkson a large snapshot of del.icio.us andon query logs of two large search engines.All of the three datasets show small worldproperties. The tagging behavior of users,which is explained by preferential attachmentof the tags in social bookmark systems, isreflected in the distribution of single querywords in search engines. We can concludethat the clicking behaviour of search engineusers based on the displayed search resultsand the tagging behaviour of social bookmarkingusers is driven by similar dynamics.