So in Mail’s toolbar, you should see an icon that looks like, well…a flag. If you have a message selected, you can click on that icon to automatically flag that e-mail with your currently selected color, or if you prefer, you can choose the drop-down arrow next to the flag to use a different color. (If you don’t see the flag icon on your toolbar, add it by going to View > Customize Toolbar and dragging it out to where you’d like it to live.)
Flagging messages is very helpful. Categorize certain e-mails as urgent or color-code them for future reference, and Lion’s Mail program makes messages very easy to find after you’ve done so. First, you’ll note that you have a new “Flagged” Smart Mailbox in your Mailbox List after you flag something for the first time; use that to view messages you’ve previously marked. You can tell how many items you have associated with each color by the indicators next to the categories.
Here’s the weird thing, though. If you’ve only used one color for flagging, you won’t see the drop-down arrow by your Flagged mailbox as shown above. Sad trombone.
This is not good, since editing the names in the Mailbox List is the only way to rename your color categories! And let’s be honest here—“red” and “orange” are not great names to sort e-mails by. So flag a couple of messages with different colors, and then you’ll be allowed to click the drop-down arrow and double-click the category names to change them.
Another quick way to find the e-mails you’ve marked is from the toolbar. As soon as you flag your first message, a new shortcut to your special, shiny mailbox will appear in your toolbar for easy access.
You can also do searches by flag name using Lion’s much-improved Mail searching (which I’ve already written a full tip about).
Or search to see all messages that are flagged if you prefer that to using your Mailbox List.
To remove a flag, select the message, click on the drop-down arrow next to the flag icon on your toolbar, and then choose “Clear Flag” (as in my first screenshot above). You can accomplish the same thing by right- or Control-clicking the message in question and selecting the option from the contextual menu.
For one final, useful way to flag to your heart’s content, you can have Mail automatically apply them as messages arrive. To do so, go to Mail > Preferences and click on the “Rules” tab. Choose “Add Rule,” and you can then define all sorts of ways for your mail to be handled, including flagging specific senders, subjects, or keywords.
Have I told you more than you ever wanted to know about flags? Well, now you can go out in the world and proclaim yourself to be a flag expert. People might look at you oddly, but they do anyway, right? No? Just me? Well, just me and Lady Gaga, anyway.