Related Clues:
- Some iPhone reading
- Some iPhone messages
- Spam, perhaps
- Encryption candidate
- Nonissue in 2016 Democratic debates
- Message with a subject line
- Some cybermessages
- Yahoo! service
- One way to send a message
- Some smartphone messages
- Text ancestor
- Fast-arriving letter
- Major cause of the Postal Service's dwindling revenues
- Outlook messages
- Letter that opens with a click