Related Clues:

• Message, small, delivered in double time
• ... online message from number one in road racing event
• 140-characters-or-less message
• Communicate a little bit in race
• Message that can't exceed 140 characters
• Limited-size post
• With a minimum of tact, little time for message?
• Casual shirt is a bit small for tenor - put that out there
• Hashtag container
• Message conforming to a 140-character limit
• Communicate with 'followers'
• People in general blocking an offensive brief message
• Message with a hashtag
• Message with a hashtag, often
• Communication with hashtags