Someone usually knows who the John and Mary are in John + Mary
forever, so this would be a chance to share that information or
defend against accusation, online.
Today walking through the forest I saw an awesome old long graffiti
on a tree in a national park with misspelled words and everything.
reminded me of the time I incised into the wet cement of a sidewalk
on my way home from school, "The Gratful Dead".
I think there already are general graffiti databases but this one
would be just for trees and would be an opportunity to share info on
some of those a really old tree graffitis.