Damn, I lost another house.
You start off in a neighborhood where not everyone is subscribing to the paper. Somehow the delivery service determines how the neighborhood views the quality of the paper, so by doing a good job you could gain more subscribers. And for some reason, you always end up at a skate and dirt park to finish off the level.
Now, it is not as easy as tossing the paper by the house. You have to either get the paper in the mailbox or on the front porch. To mess you up, there are runaway strollers, random rolling tires, cars that don't stop, and angry dogs.
This provided entertainment without all the flashiness of other games that were available at the time. Paperboy was all about getting that paper to the customer. See, it has an educational value related to work ethic.