You can now license out your photos with Creative Commons on 500px
500px has rolled out a new feature, finally allowing users to mark their works as Creative Commons, matching functionality that’s been in place on Flickr for years. When you upload an image to 500px now, you have the option to allow licensing under one of a number of Creative Commons licenses, including Attribution, Attribution No Derivatives, Attribution Share Alike, Attribution Non-Commercial, Attribution Non-Commercial No Derivatives, and Attribution Non-Commercial Share, depending on how much freedom you want to give people to edit and share the photo.
For photographers who don’t mind their work being used as long as their name is still attached, this allows for an easy way of marking your photos as such. The Creative Commons licensed images have been gathered on a dedicated page for easy access, so that people on the hunt for images will be able to track them down more easily.
from PopPhoto.com: Main Feed http://www.popphoto.com/news/2012/11/500px-now-allows-creative-commons-licensing