Yes, indeed. It can become a source of income and once you earn enough it could be a job. Once it is a job for you, and you earn enough to work with affiliate marketing full time, it would be like a career in that you can increase your income based on the performance of your work.

See all questions and answers in my affiliate marketing FAQ

This question was answered by Aleksander Blomquist. He started out with affiliate marketing back in 2008. As of 2020, he is a full-time affiliate marketing guy with two businesses focusing on creating websites from scratch and monetizing them with affiliate programs.