  In recent years, the amount of information on the Internet has increased
exponentially developing great interest in selective information dissemination
systems. The publish/subscribe paradigm is particularly suited for designing
systems for routing information and requests according to their content
throughout wide-area network of brokers. Current publish/subscribe systems use
limited syntax-based content routing but since publishers and subscribers are
anonymous and decoupled in time, space and location, often over wide-area
network boundary, they do not necessarily speak the same language.
Consequently, adding semantics to current publish/subscribe systems is
important. In this paper we identify and examine the issues in developing
semantic-based content routing for publish/subscribe broker networks.
