Zeitgeist is a service which logs the user's activities and events (files opened, websites visited, conversations hold with other people, etc.) and makes the relevant information available to other applications.
It serves as a comprehensive activity log and also makes it possible to determine relationships between items based on usage patterns.
This package contains zeitgeist-datahub, a daemon which starts together with the main engine and inserts information collected from GtkRecentlyUsed, KDE's Recent Documents and several other sources into it.