PowerPoint presents a case for competing rhetorical analyses.  David Byrne argues that PowerPoint has its own aesthetic value, while skeptics like Tufte disagree.  How can such a pre-packaged form of presentation replace the traditional arts of oratory, epitomized by the Gettysburg Address?   Certainly Peter Norvig's satire and John Raffensperger's elegy use PowerPoint with the Great Emancipator's famous speech to radically different ends.