Back issues are all the old comic books that weren’t sold at the comic book store when they were first published. They’re stored in big long cardboard boxes, and they entice fanboys to search through all of them. Apparently comics that weren’t interesting enough for the comic fan to buy when they were new grow in appeal once they are put in bags and shoved in a cardboard box. It’s like showrooms at furniture stores. By “displaying” the comic like it will be “displayed” at home, the fanboy has an easy time visualizing what it will be like when he brings that comic home.