All sources were created for a particular individual or group of people. Based upon what you know about the creation of the source, you need to identify who the original reader or viewer was supposed to be. Some sources may address their intended audience, but most of the time you will be required to make an informed decision regarding the original reader or viewer.
The Gallic Wars, created by Julius Caesar himself during his campaigns in Gaul in the 50s BC, was written primarily for the residents of the city of Rome.
The magazine article was written to not only inform their readership, but also to be entertaining.