Duncan asked me if I'd respond to this message now, so here I am...

Conversant supports categorization of items (messages) through custom fields. There are currently five different custom field types: dates, short text (good for keywords), long text (good for summaries, additional info), popup menus (good for "apply only one category"), and list/combo boxes (good for "choose at least one category").

A conversation can have any number of custom fields, and custom fields are fully indexed and searchable with the messages.

http://support.free-conversant.com/discussionThreadOutline$msgNum=3214

I think that answers the question pretty well. :-)