Multiple From addresses

If an e-mail account has more than one valid From address (for example, if you use jk@example.com as an alias to joekissell@example.com), you can configure Mail to let you use any of those addresses when sending a given message from that account. First, choose Mail -> Preferences, click on the Accounts icon on the toolbar, select your account, and click on Account Information. Then, in the E-mail Address field, enter all the addresses you might use with that account, separated by commas. Close the Preferences window and click on Save. Now, when you compose a new message, you can choose any of those addresses from the From pop-up menu below the Subject field.

Super praktisch!