Statistics "a la" Google analytics in real time. They also provide a rich client - erf, if a java application can stand for a "rich" client. They also provide the ability to "tag" a user in order to track its data all over the statistics interface.
about: The sfStatsPlugin provides an easy way to display charts based on data you already own. Whether you want to follow the global progress of your application usage, or to analyze precisely how many specific actions were done by users under particular conditions, this plugin is for you.