And do people with the normal flu wear face masks or do only the people with swine flu wear the mask?

Both: People with known flu of any type should wear a face mask. Any flu virus strain is considered highly contagious.

Flu mask: There is currently no swine flu in the United States. The people using masks do so for many reasons, often just common cold; and probably mostly because they're hoping to protect themselves from colds and influenza, not because they have any infection themselves.

Some basics: Some cultures routinely use face masks with any infectious cold or flu in an effort not to pass germs to others (a cultural taboo). I saw this frequently while working in the orient. It has not caught on as the norm in the US & any such use is an individual choice. It has NOTHING to do with the type of illness.

Face masks: People with many different types of infectious diseases wear face masks. It is mandatory in my state if in public due to the COVID 19 pandemic.