When you get a commission by selling different kinds of products whether physical or digital on the net, it’s known as affiliate marketing. You sign up with affiliate sites like Commission Junction and Clickbank and earn money by promoting and selling their products. You can use different methods to promote these products like article writing, niche site building and advertising on the site via banner ads. You can even use Twitter and other social networking sites to sell these products. As you grow more comfortable with the idea of affiliate marketing you can earn a lot of residual income for a one time effort from sites as long as they belong to you.