Wow! Here is an amazing ad from the fall of 1943. This scan is from the back cover of Leading Comics #8, and it's interesting as it features both DC/National and All-American titles. Prior to this (I'm not sure when the change occurred), you'd see ads for one line of titles and a separate ad for the other line of titles. I guess that they decided to focus on branding the "Big Eight of Monthly Comic Magazines". Fiction House would later use similar marketing for their line of comics - I'll see if I can dig up one of those late 40s ads. Keep in mind, Batman, Superman, World's Finest and Wonder Woman were all still quarterly titles at this stage. I love this kind of ad, because it is a true snapshot in time, giving you a real sense of what was happening at DC at that time. Could you imagine owning all 8 books? I'm guessing Edgar Church did.