Wanted to give a shout out to USE BOTH SIDES, another grassroots campaign aimed at saving paper. This initiative out of the UK has a simple goal, as stated on their website:
We hope to convince everyone that we can - and should - use both sides of the paper.
There's a nifty intro video, as well as several different poster designs. They've also started a Facebook group.
Thanks to Michael Leddy, both for leading me to the Use Both Sides campaign and for posting a link to Margins on his blog Orange Crate Art.