One of the confusions that I have heard repeated a number of times
at our site, is people looking for the Mosaic server. Many applications
are shipped with a client and a server component, so it makes sense when
people ask if they need to install the server software.
A decent diagram of the web clients and the web services which shows
how the various applications can plug & play would go along way to
reducing end user confusion about the various roles each tool
provides in navigating through the web.