To further the plot of the show. Honestly, I am hoping that in season two they finally figure out each other's identities because this is getting ridiculous. I'm hoping the reason Marinette and Adrian can't tell each other's identities has to do with the magic of the miraculous. So that you would only know the other person's identity if they told you. Otherwise it wouldn't really make sense how they (and the rest of Paris) couldn't put the clues together.
