When I read the title of this thread, I thought it would make for a great short story. The Mysterious Proofreader's Mark. The plot would revolve around a writer who can't decipher an editor's mark, so he does a little digging, but to no avail. Meanwhile, the editor disappears and when the writer pays a visit to the editor's house, he finds the same symbol etched thousands of times in every room of the house--as if the editor had gone mad and carved it into the walls, the tables, the TV screen, even the floors, and then disappeared.
The writer's quest to discover the meaning of this curious symbol takes him on an adventure full of action, intrigue, suspense, danger, and maybe even some romance. Will the writer find the missing editor? Will he discover the meaning of the mysterious symbol? What will he do when he unearths a global conspiracy? Oh man, this is going to be such a great story.
...I'm sorry, what was the question again?