Two distinct approaches describe the process of indexing. The document
-oriented approach claims that indexing summarizes or represents the c
ontents of a document. The user-oriented approach requires that indexi
ng reflect the requests for which a document might be relevant. Most i
ndexing, in practice as well as in theory, subscribe to both, but the
document-oriented approach has enjoyed most visibility. While request-
oriented indexing is a user-centered approach, it is very difficult to
implement with human, a priori indexing. Automated indexing with its
dynamic and flexible nature is most fit to tailor indexing to requirem
ents of individual users and requests, yet most of current research in
the area focuses on the development of global methods. Regardless of
the method, user-centered indexing cannot be developed before searchin
g behavior is understood better.