For missions there is an application of increasing awareness of the expectations and reactions of stateside people to the missionary's communication. When mission teams better understand the perceptions of the people they are trying to reach with the gospel their communications improve. The same applies to communication with people in the states. The more you know about your target audience, the better you will be able to get your message to them. Your team wants to build name recognition and awareness in your supporters' mind.
Focus groups can help mission teams get a peek into the mind of the supporter.
The main thing with such groups is that they be informal and not follow a list of questions, otherwise that would be a survey. Otherwise, your list of questions might get answered and your pet prejudices might get falsely confirmed. The questions would likely reflect your way of thinking and not theirs. Meanwhile, they would not be telling you what is really in their minds. Then if you find the Focus group format useful you can opt for larger groups later.