To build an email list that generates sales then you need to do more than just promote products for sale. Think about it.
It is possible to write your own unique website content, but only to a certain extent. In the early stages when your site is still small, it's fairly easy to keep it updated on a regular basis. However, once it's been further developed and you're established and your website's size has increased, trying to keep up with the necessary content creation on your own can become counterproductive as your precious time will be taken up by writing.
The scam warnings we publicize normally originate from calls from readers and businesses, or alerts from government agencies and the Better Business Bureau.