Promotional mail tagging & filter with spamassassin & dovecot.

Theses Days we receive many Promotional mail , be in form of advertisement, newsletter, mailing list, some bulk marketing mails...etc. which irritated many specially in work mailbox. Google's Gmail has got a better algorithm to filter and put it under tab. but to have similar feature we need to keep on adding filter on our local email clients. to have server side filter with global tagging is now possible with spamassassin with dovecot sieve as filter on server side.