Superman’s a pretty big character.  He’s one of the most recognized icons in the world.  So it was a big deal when, almost a year before it happened, DC Comics told everyone they were killing the icon off.  The even transcended the comic world to becoming a media frenzy all the way until the record-breaking release of Superman #75 where lines poured out of comic stores as everyone and their grandmother ran to buy several copies in the hopes to retiring early.  The 5 million print-run did away with a real second-hand market, but the event itself shocked some life into the comic book industry, from collectors and headline grabbing events from publishers.  And high-profile deaths (and returns) have stayed ever since.