While I was doing WordPress speed optimization I noticed lots of people needed it, but very few people supplied it (there were a lack of services and tutorials when I researched Google). I also knew hosting was the #1 factor of website speed factor and these companies paid up to $200/sale. Hosting is a competitive space but the commissions and lack of supply enticed me.
However, here is where many affiliate marketers fail. Just because you advertise a product or service for a company, it does not entice a blog or website visitor to purchase it. You have to usher people to affiliate marketing opportunities. Not by throwing a random link on a website, but by helping a website visitor understand how a product or service will fulfill a need they have.