Spamassassin vs Amavis + Spamassassin

[feablee]

Hello,
Could someone explain me what is difference between using Postfix + Spamassassin and Postfix + Amavis + Spamassassin. Why use Amavis as a content filter? Cant be only Postfix + Spamassassin?
I'm a bit confused.

regards,

[falko]

As far as I know, you cannot integrate SpamAssassin directly into Postfix, that's why you need tools like amavisd or procmail. SpamAssassin doesn't deliver mails, it just calculates a score.