In theory, the original is the one that appears first. In practice, this won't work, because a targeted spider of, say, the Oatmeal website will be able to gra

In theory, the original is the one that appears first. In practice, this won't work, because a targeted spider of, say, the Oatmeal website will be able to grab new material and post it elsewhere (with modified headers a bit earlier than the original...) long before any generalized search engine swings back around again to check for new content.