There is no dark side of the moon. Matter of fact, it's all dark. The only thing that makes it look light is the sun. The typical conception of a resource like "Arxiv" or "Wikipedia" is summed up in the name: it is an archive or an encyclopedia that anyone can edit . "Stack Exchange" is somewhat less self-descriptive -- but nevertheless, the emphasis on "exchange" is apt, since this site is not quite a gift economy in Eric S. Raymond's sense, but rather a place where questions are exchanged for answers, and both are exchanged for reputation in the form of points and badges. Nevertheless, in broad brushstrokes all three resources have something much more essential as a common basis: they all grow in the course of use. That said, they do not typically transform radically along the way. Arxiv remains an archive; Wikipedia remains a wiki and encyclopedia; Stack Exchange is and always will be a Q&A site focused on questions wi...