Related Clues:

• It might have an attachment
• Inbox contents
• Hit "Send"
• Inbox buildup
• It's often filtered
• Modern means of relaying jokes
• Spam, sometimes
• Alternative to the post office
• Unstamped letters
• Bottle contents, maybe
• Some have worms
• Send with a click
• Inbox item
• Cyber-letters
• Inbox accumulation