The disc with the Master PC 3.0 on it was sent through the mail to the home of one of the people of the Marvel / DC mixed Universe. Which home? A hero's? A villain's? A normal person? It didn't matter as the disc had a little command on it so the person would at least load it up onto the computer to see what it was. If they didn't use it, the program had bonus features which could be triggered to make sure it was used.
So who would gain the program? And how it can help the owner?