I'm trying to understand how the spam checker works and am hoping someone can clear up a few things.

1) Admin guide speaks of using the "Junk" button when spam makes it's way into the inbox. This will help "learning" of what to classify as spam and what not to. Does that button do something special or does the act of moving mail to the junk folder accomplish the same thing? Specifically, if I use Thunderbird or some other app to move mail to the junk folder will the "learning" aspect still be accomplished?

I guess the same sort of questions apply to items mistakenly marked as spam.

2) Tweaking the filters... Are there some guidelines to how to do this? I have the settings on Kill 75 and Tag 33. (Default?) With these setting stuff is getting caught, but I have one user that is still getting a larger amount of spam in the Inbox than I'd like. I've seen mention of looking in the headers to determine the ratings that were given, but I'm not sure what I'm looking for and if what I see is good or bad. Is there a discussion somewhere that might help me further tweak Zimbra?