Idea courtesy of Regretsy. At least some people will credit them for finding this stuff. Post'it War is an amazing new Tumblr site dedicated to 8-Bit art made from post-it notes. Just look at what users are doing on any blank space they can find in France.
Post'it War has very little written content on the site. What it comes down to is some people in France started posting post-it note art on any blank space they could find. They took photos and uploaded them to this site. That was a month ago. Now there are over a thousand images uploaded to the Tumblr and growing every day.
The concept, near as I can tell, is to "declare war" on your friends and neighbors. You find a way to tag a place they'll be with post-it note art and they, in turn, do the same to you. It's a fun form of graffiti that can't possibly cause any lasting damage. If someone wants the piece down, they need only pull the post-it notes off the walls.
A person could get lost wandering through that gallery. I know I have. It's for good reason. The site is non-threatening mostly-fan art done for public consumption. It's genius. It's like those LED throwies from Graffiti Research Lab, only not tossed up on the sides of bridges. It's completely reversible graffiti and public art that can be changed out as often as a person is willing to invest the time to do it.