It depends on who you speak to, as you can see from the responses to your question. It varies between person to person. I have found that writing on hubpages has been good for me - take for e.g. my hub - "Best gift for my daughter – Got her a nintendo ds for girls in bright pink"
Since I have put it online it has been averaging 55 views per day, I am now working to alter my other hubs so that they also turn out that kind of traffic - that should generate me sufficient passive income. I can then look to complementing that with other schemes like setting up a blog, writing for other sites like Xomba etc.
All the best