You hear Internet marketers talk all the time about building an email list. I agree this is important.
In my mind the real reason that this is important is you can use your email list as a traffic generation strategy.
A good way to do this is when you make a blog post send out an email to your list. Include the first paragraph and then a link to your new blog article.
Rather than describe everything about it use that first paragraph as a way to generate curiosity. Then tell people to click here and have those words linked to the blog post URL.
A certain percentage of people on your mailing list are going to go and see what you have in that one article. This is where you have the opportunity to make some money.
A nonthreatening way to do that is to hyperlink keywords within the article back to products you sell. Then let people find those links and if they want to purchase something they will.