Last month, Google released Priority Inbox, a system that learns which messages are the most important to you and highlights them automatically over time. It's in beta right now and Google is slowly turning it on for its users. If you're tired of waiting, or if you use Apple's Mail and not Gmail, you'll appreciate this setup from Ben Brooks.
Ben explains how a combination of rules acts as his "priority inbox" for Mail. He's got some basic rules in place, like one that identifies messages from Apple and one that files backups away. Others are more clever.
For instance, he's written one that first notices if his work address is in the CC field, and then checks if his name appears in the message body