As someone who shoots and sells landscape and cityscape photography, I am indeed interested in what sells. But not what others sell, so that I can replicate it, but what sells of MY photography. I shoot what I like, process the way I like, and only then I pay attention to what sells of THOSE. If something doesn't go, I'll keep shooting it for my own pleasure, or find a venue where it might go. There is a difference what people might want to put on their wall, what an ad agency might consider suitable, or what magazine editor might like. So, yes, I alter my sets of images based on target audiences, but that does not mean I need to alter my photography. I still raise my camera only if something speaks to me.