Ethics is not a word you hear a lot when it comes to SEO affiliate marketing. People build entire businesses around just a few top keywords. The problem with building a business on keyword fads is that they often go stale. A word that might seem like a good keyword at the moment, it is probably not a good keyword two years from now.
Trends can make you a profit in the short term but you have to be fast. This means having the money to invest in unique writing copy (or the tons of time to write it yourself) and the capacity to pay money to sites to index your site quickly. You also need and the ability to keep your business ideas a secret. Many people have fantastic ideas as to what to market but usually someone else has beat them to it.
If you dont have the financial savvy it takes to throw up sites quickly, the idea here is to choose a theme that appeals to many, yet is somehow specialized enough to make it unique. Then try and give people information that they will find valuable. The real truth is that some of the richest affiliate marketers became rich because they had some integrity and interest in their product. A good example is that 18 year old whiz kid who...