We show how personalization techniques can be exploited to implement
more adaptive and effective information access systems in electronic
publishing. We distinguish persistent (or long term) and ephemeral (or
short term) personalization, and we describe how both of them can be
profitably applied in information filtering and retrieval systems
used, via a specialized Web portal, by physicists in their daily
job. By means of several experimental results, we demonstrate that
persistent personalization is needed and useful for information
filtering systems, and ephemeral personalization leads to more
effective and usable information retrieval systems.