Earlier today, 500px announced that it would be getting into the licensing game with a new commercial licensing site dubbed 500px Prime. Announced on the image sharing site's blog, 500px is painting Prime as a revolutionary commercial licensing marketplace that will "fundamentally change the way photos are licensed."
A new licensing agreement that 500px has come up with, has photographers agreeing. With 30% going straight to the photographer, no if's or but's about it. Also you will have the advantage to see how your images are being perceived.