Take a look at how 500px have built the rating system. They make it really addictive to post content & get high scores & praise from the community. This is beca

Take a look at how 500px have built the rating system. They make it really addictive to post content & get high scores & praise from the community. This is because as soon as you click on an image it makes a big feature of the person that posted it. It's very easy to then click around on other items that person has posted (probably similar high quality) Contributors want to become known for posting great content, users start to recognise who the great contributors are through their avatar/profile building up a sense of community.