Related Clues:

• It might be spam
• Accumulate, with 'up'
• Computer message
• Modern posting
• Post sans postage
• Spammer's medium
• Write without pen or pencil
• Online memo
• Place for an emoticon
• Call alternative
• Cyberspace note
• Stock ending?
• Correspondence sans stamp
• It doesn't leave a paper trail?
• Virtual inbox fill