There is another factor that you need to consider as well.
Online advertising program like AdWords are still extremely effective, but they are becoming less so as people become more aware that when they see ‘Sponsored Links’ on a page, it means that they are looking at paid advertising.
People in general and internet users in particular seem to have an increasing aversion to visiting sites that use paid advertising to promote their products and services, perhaps because they believe that sites that pay to advertise will always be those that are trying to sell them something.