Real world business need
One of the goals for the example database is as a demonstration of how it might be used in a real world environment. Given that no one has volunteered their companies database application yet, we are forced to create a virtual real world business.
The goal is not to create a full blown business system for these scenarios but to either concentrate on one part of their business or a little part of each part.
Here are a couple of ideas for these fictitious firms: