2nd tier. If you are an affiliate for a particular program and you refer others to sign up for that affiliate program, a 2nd tier program will pay you when the affiliates you referred make sales. For example, I am an affiliate for Ultimate Bundles. If you join their affiliate program via my 2nd tier affiliate link here. I will get a small percentage of any sales you make going forward.
Cost per click was more common in the early days of affiliate marketing but has diminished in use over time due to click fraud issues very similar to the click fraud issues modern search engines are facing today. Contextual advertising programs are not considered in the statistic pertaining to the diminished use of cost per click, as it is uncertain if contextual advertising can be considered affiliate marketing.
Affiliate marketing currently lacks industry standards for training and certification. There are some training courses and seminars that result in certifications; however, the acceptance of such certifications is mostly due to the reputation of the individual or company issuing the certification. Affiliate marketing is not commonly taught in universities, and only a few college instructors work with Internet marketers to introduce the subject to students majoring in marketing.
If the answer to each of these questions is a resounding yes, rather than jumping to conclusions immediately, take time to research whether or not others are out there making a sustainable affiliate income from products and content in this niche. In a sense, competition is a good thing here—it'll help you validate your idea and prove that it's worth of building a business around.