Folksonomies indexing and retrieval in web 2.0

In Web 2.0 users not only make heavy use of Col-laborative Information Services in order to create, publish and share digital information resources - what is more, they index and represent these re-sources via own keywords, so-called tags. The sum of this user-generated metadata of a Collaborative Information Service is also called Folksonomy. In contrast to professionally created and highly struc-tured metadata, e.g. subject headings, thesauri, clas-sification systems or ontologies, which are applied in libraries, corporate information architectures or commercial databases and which were deve