Have you tried upload-and-get paid sites?

I know my response isn't necessarily going to be helpful to you, but I too am curious about that. Could someone explain what type of content will get you paid and the general guidelines for these sites? I've been looking a lot into online earning lately and this is one of the things I've come across that I haven't gotten to do a great amount of research in. I actually don't even think I've seen it discussed in great deal on this website which could point to the effectiveness of it if it's not being discussed.