Here, Thunderbird appears to have built-in support for Bogofilter DSPAM POPFile SpamAssassin SpamPal No mention of SpamFighter. If SpamFighter inserts special headers then you can create a Message Filter to look for them and act on them. You'll probably need to define a custom header term for the Message Filter tool. The Junk controls in Thunderbird are a separate Bayesian rule-based system and rely on training (i.e. the user marking messages as Junk or Not Junk as appropriate.) No connection with filters or anti-spam tools such as those listed above. Use J or j or '''right-click|Mark As''' to set a message's Junk status. The Junk Controls part of account settings provides some adjustments, such as moving manually-marked Junk straight to the Junk folder. If you use Thunderbird and just keep accumulating messages, the files storing the messages will just get larger and larger, and the process of indexing them and searching them gets slower and slower. Archiving allows less frequently used (i.e. older) messages to be moved out into their own files, so we have a large number of smaller files rather than a small number of huge files. By default, the Archive function stores messages according to the year in their date entries, and archiving can be set to preserve any folder systems you have set up. I can't see any good reason to send Junk or Trash to Archive; both are by definition designed for messages that aren't useful (unless you're studying and researching spam and junk email). The main point of these folders is to temporarily hold messages that have been identified as suspicious, so you can veto and recover them if incorrectly categorized.