Importance Markers
Each email has an importance marker immediately to the left of the sender’s name in the Inbox list. It looks like a flag or arrow. When Gmail identifies a particular email as being important based on its criteria, the importance marker is yellow. When it is not recognized as being important, it is just the empty outline of the shape. At any time, you can click the importance marker and change its status manually. If you want to know why Gmail decided a particular email was important, hover your cursor over the yellow flag and read the explanation. If you disagree, just click the yellow flag to mark it unimportant. This action teaches Gmail which emails you think are important.
How to Turn on Priority Inbox
Here’s how to turn on Priority Inbox in the Gmail Settings:
How Gmail Decides Which Emails Are Important
Gmail uses several criteria when deciding which emails to mark as important or not important. Among the criteria are:
Which emails you openWhich emails you reply toWho you send emails to and how oftenKeywords that occur in emails you usually readWhich emails you starWhich emails you archiveWhich emails you deleteWhich emails you mark important manuallyWhich emails you mark unimportant manually
Gmail learns your preferences from your actions as you use Gmail.