We propose a model that assists in understanding indexing on the World
Wide Web (WWW). This model specifies key feature of indexing strategi
es that are currently being used. We also present an experiment assess
ing the validity of Inverse Document Frequency (IDF) as a term weighti
ng strategy for WWW documents. The experiment indicates that IDF score
s are not stable in the heterogeneous and dynamic context of the WWW.
This research recommends further investigation to clarify the effectiv
eness of alternative indexing strategies for the WWW.