We target whatever the client s asks us to as long as there is budget. Sometimes, targeting different cities will require a different campaign for each. Other times (if the cities are close together) we will run a radius or some other targeting, and break up the campaigns in a different way. If you are running national campaigns, or statewide with a lot of big cities (think Texas or Cali), you will definitely want a campaign for each target area. Way more control and optimization possibilities.