The Junk E-Mail Filter appeared in Mac OS X version 10.2 and is likely here to stay. It has many features you’re probably already aware of, including message titles appearing in color if Mail thinks the message is a spam message. Your job, the first month or so, is to “teach” Mail what is and is not spam.
Tip: Make sure Junk Mail Filtering is enabled before continuing. Choose Mail>Preferences>Junk Mail. Verify that Enable Junk Mail Filtering is checked.
After you select a message to read, you can decide if it’s junk or not. If Mail thinks it
is junk mail and it is, do nothing. If mail thinks it is junk mail and it isn’t, click Not Junk. [See Image 1]. If mail does not think it is junk mail and it is, click Junk at the top of the Mail window.
It should take about a month to train Mail so that it becomes 95% accurate in identifying spam:
1. Choose Mail>Preferences>Junk Mail.
2. In the When Junk Mail Arrives choices, select Move It To The Junk Mailbox (Automatic). Don’t forget to check this mailbox occasionally, as well as any other folders you’ve created, and delete the contents. You don’t want to create clutter yourself!