Well sometimes people like to keep their style to themselves so it doesn't end up like the whole c4d/fractal spamming thing I used to combine smudge, c4d, fractal and clip masking but I did it in a way that made people love the outcome. I mean smudge is pretty simple you start off with a 20-30px hard brush set on like 20% opacity to define the shapes and flow of the smudge then come in with a 2-4px hard brush set on 80-90% opacity to add the detail to the shapes and flow I created with the larger brush.
