[alexqgb]

If you're replying to someone you don't mind getting snarky with, you can always sign your message "Sent from my Atari".

[reinhardt]

I use "sent from my rotary phone"

[chronomex]

"Sent from my Dymo Labeler" here

[manojlds]

Sent from an imaginary device.

"i"pad - get it? :)