Originally Posted by Pornopat

Now that is where your reasoning goes wrong. Some niches work better with certain mgp's. To give a very clear example : A thumb of a teenie will get you very little clicks at a site like mature-post.
Every site has their fanbase of bookmarkers and google traffic (this is the quality traffic you should be after). The bookmarkers have their preferences en the google traffic is looking for something specific. You will see this back in sales AND the amount of traffic that goes to a gallery.

I do both by the way. Paid spots and submitpasses. I make a nice profit on both and I know more people that do. These people know what they do.