I stopped using 500px long time ago, as a professional photographer my main concern was that they: TAKE the TOTAL ownership of uploaded content. Might not be the case for pro account but for the free ones it is in their Terms and Conditions. Recently I was "spammed" to check out a site called YouPic. I must say I really enjoyed the Experience, much more 2015 than 500px. Also as you might have guessed I totally checked out the terms and conditions on YouPic and they do not steal rights to the photos. 500px does unfortunately. I think they will lose many users to the new kid in town. The concentration on YouPic seems to be about inspiration and getting better photos. And the amazing 10 000 views in less than 2 days on my photography was a wow experience.