MemberPress is a feature-rich plugin that will enable you to turn your WordPress blog into a fully functional membership site. Depending on how you want to run your membership site, you could have a mixture of free and premium membership plans. Premium plans could include no adverts, free downloads, access to extra content, membership forums, and much more. However, it is important to remember that if people are going to pay to view your content then it must be high quality. Otherwise your members won’t renew their subscriptions when the time comes.
Not necessarily, but a blog is really the best promotional tool. With that said, you can always use methods such as PPC or advertising to promote a product. This is more like hit-and-run affiliate marketing, however. The best way to make the most out of your affiliate marketing opportunities is to have a blog and use it for hard and soft promotion.