I was at a brilliant conference last Monday run for charity and third sector communications peeps (like me).
One of the seminars I was in talked about 'Slactivism'. This is activism that doesn't take a lot of work on the behalf of the participant. The example he cited was people turning their Twitter avatars green during the kerfuffle over the Iranian election to show their support for the opposition party.
It was an easy thing to do and so people did it. I think Superbadger works much the same way. Just 'sign' the email and press send. Piece of cake.
I wanna see more charities do this. I'm busy and I want to support you, so don't make it hard for me to do so.