http://buildingabrandonline.com/garyakin/should-you-use-free-or-paid-advertising-and-which-media/

You probably have heard the suggestion that you should only take on additional lines other than affiliate products after you master your main product line. It is suggested that you use somewhat the same approach on advertising media. Pick a platform that is most interesting to you, master that platform and then add on others. If one is not careful in this business, there is a tendency to take on too many things at once and not do well in any of them.