Related Clues:

• Sends with a click
• Target of some filters
• Forward, perhaps
• Where all addresses include @
• What a server may serve
• Letters that can arrive at any time
• Write, these days
• Office communication
• Virtual inbox filler
• Postal alternative
• Something you click to open
• Deliver spam
• Send, on a computer
• Cyber-missive
• It might have an attachment