The title usually gives you a hint of what's going to happen. And one shall fall, for instance, may create the appropriate suspense without telling you who will fall. They may draw the reader's attention to a single character as well. Sometimes, though, they work as mere reminders. For instance, if the Avengers were trapped in the previous issue, the title of the following book might be Avengers in Chains. Bear in mind that comic book are published monthly, so it's no wonder if you've already forgotten what happened the month before when you open the latest issue.