What is the incentive for people to post their articles on http://ezinearticles.com/ ? Do other people just use these articles on their sites and you get a free backlink out of it?
Definitely. The publishers who sign up with the ezine have to use the articles without changing any content along with the source where the backlink is usually located. It acts as a source of viral marketing if your title is catchy and content is unique and interesting...
You write your article and, in the resource box, include a link to your site. It gives you a backlink plus I personally get lots of traffic directly from the ezinearticle site.