There's also a common sig about "Please think twice about printing this email" with a wingwings of a little tree. That turns into some plain character as well. Maybe G? I kept wondering why everyone was ending their emails with G.

I also wonder how much energy is collectively wasted sending that extra line in every email. It must add up to something from a storage, energy use, rendering, etc perspective. I wonder if it offsets any behavior changes that may help the environment by those who actually don't print. I doubt that little message is going to stop anyone from printing.