Per default when you deactivate the plugin, the settings and database tables are -not- removed.
This is helpful if you are doing just simple debugging and want to make sure the problem is not with this plugin.
If you want to remove all traces and settings of the plugin when you deactivate, make sure you go to the Tools page and activate the “Remove settings when deactivating”
This will also clean out any event logs, visitor log and so on.
