Use the subject line to specify your message. A clear and specific subject line will preview your message for your recipients, making their reading easier and aiding their understanding. You will also be helping recipients to sort and find your messages later, especially if you write a separate message for each topic you address. If your message includes a sizable attachment that might be slow to access from a wireless mobile device, identify it here in brackets—[BIG DOC], [BIG PIC], [AUDIO], or [VIDEO]—so that your recipients know whether to look at it immediately or wait for a more convenient time.