This part is shown only when the "Enable Anti Spam user self control" option is checked in Administrator Settings.
It allows user to control his/her own settings of Anti Spam engine so he/she can manage this settings according to the Anti Spam efficiency, etc.
For Administrators: Also the Processing Mode for Instant Anti Spam and Challenge Response has to be set to selected accounts only or to all accounts except selected in Merak Config to have a proper functionality of this feature
Instant Anti Spam checkbox enables/disables Anti Spam engine for appropriate user completely. This is also the point why the Processing Mode for Instant Anti Spam can't be set to Process All.
Challenge Response checkbox do the same but for Challenge Response instead of Instant Anti Spam.
Spam Folder mode determines if the Spam folder will be created in user mailbox and if messages marked as Spam will be placed to that folder instead of Inbox folder. If default is chosen the settings which is set for whole Instant Anti Spam engine is used.
Spam Detection Level determines how strict is Instant Anti Spam engine in marking messages as Spam. In other words, if only low probability is needed to recognize message as Spam (High level) or if the message has to have high probability to be marked as Spam (Low level). If default option is chosen the default Instant Anti Spam settings of this feature will be used.
For Administrators: The score for each level can be set in spam.dat file in Merak\Spam\ folder.