The term “fly on the wall” in a marketing or public relations sense simply means an unseen observer. In the documentary world, filmmakers know that when their subjects have the camera on them, they perform differently than they do while they are alone. A fly on the wall wouldn’t draw any attention from the subjects being studied, and so they would act completely natural, and say what was truly on their mind.
In marketing and PR, getting that fly on the wall perspective means that you are able to dig down deep and figure out what a customer really wants, or in a public relations sense, what someone truly thinks. There can sometimes be a difference between best marketing practices and how marketers actually discuss them.
When you are talking about a fly on the wall perspective when it comes to PR and marketing, it will depend upon what sort of job you are doing to determine what location you want that perspective to be in. PR is generally defined as the department of a company that is responsible for its relationship with the public. Marketing is slightly different. Marketing is how that company presents products and services that it is trying to get the customer to buy. Both of these jobs are similar, but they are also quite different.
So, fly on the wall can be defined a few different ways, depending upon which area of business you are focused on, and who you are trying to package a company for.