When you send out your newsletter, you need to archive the article on your site. Each article should be on it's own page with an index to the articles on another page. A link to your index of archived articles needs to be on your navigation bar. You can see an example on this site:
http://www.AtHomeBusinessPortal.com/newsletters
Here are some of the reasons you need to do this:
1. It adds content to your site. The search engines love content. They will send visitors directly to your article pages. Your navigation bar will give those visitors a chance to visit the parts of your site that make you money.
2. It gives people a reason to bookmark you site and return often.
3. It gives people an idea of what they will receive if they sign up for your newsletter. A higher percentage of people will sign up if you have an article archive.
4. At the end of each article, you should have a courtesy notice like the one you see at the end of the articles on the above site. Some people will reuse these articles and include a link to both the author's site... AND your site.
5. You should also solicit articles from other authors. More authors will submit articles if they know you will be archiving them on your site.
6. There is a chance that some search engines will eventually ban any site that is low on content. An article archive makes your site a content site is everyone's eyes. It's insurance against such an event.