A foundation of Facebook advertising is the ability to segment your audience to serve relevant, tailored creative to different users.
The ad that is served to one person could be very different to another, specifically because you want to communicate with them in different ways. If there was one ad that went to a 25 year old man, and the other went to a 50 year old man, there wasn’t any way for that woman to know what you were saying to men. But this is changing.
Last month, Facebook announced drastic changes to its rules around ad transparency.