Shopping on the Internet has become a convenient way of purchasing commodities
of choice. With the boom of e-commerce, online
sellers are flooding the market with their products. Personal
agents have been developed that assist users by providing need-specific
information which are obtained by generating, filtering, collecting, or
transforming information available on the internet. The use of ontology
for domain-specific search and its usage for developing ``buyer's agents''
can be potentially fruitful. We believe that assisting users to reformulate
queries to maximize the quality of retrieved information will be a key
enhancement of agent technology to information retrieval. To provide
this functionality, the use of a rich domain ontology will be necessary.
In this paper, we first identify the types of query reformulation that
we believe will be particularly useful and the kind of information
to be represented in domain ontologies to enable this functionality.
We also compare three example domains to identify domain characteristics
that determine the relative difficulty of providing effective query reformulations.