1) Advertisements. There are many corporations who will be willing to pay to put their banners and ads on a list with many subscribers. Selling or renting out lists is not a good idea so rather than doing that, many companies would just rather place ads with lists that have a huge subscriber base. Your newsletter could be placed with many ads and each one spells money.
2) Have affiliations with other companies that have at least a semblance or relation to what your site is about. Here other companies will provide links and brief descriptions of what they offer, products and services. With every click made on the link that directs or leads a subscriber from your list to their site, the company will pay you. This is pay for performance.
3) Make deals with other companies by asking for a small percentage of sales done through your list. With every sale done by customers that have come from your list and have gone there because of your newsletter, the other company will pay you a small percentage of your sales.
4) You may also get products from other sites on a consignment basis and sell them to your list via your newsletter. Place descriptions, articles and photos of the product in your newsletter. There will be those who will buy from you and when that happens, you can order the product from the other site and sell it to your buyer.
5) Sell e-books or a compilation of your articles on your list. Manuals and how-to articles are in great demand. Many people will be willing to shell out money to gain knowledge about a certain topic and subject. With your existing list trusting your expertise in that area, an e-book could be offered and sold or used as an incentive.
6) Create a network out of your list. Get people to invite more people to view your site and subscribe to your list. The larger your list is, the more people will be able to click on your links and affiliate links as well as make your advertisement rates higher.
7) Subscribers are willing to pay for information if they know that it can be trusted and relied upon. Use your list to get more and more people to subscribe to you as well as browse your site. Lastly, you can use your list to earn money by making them your partners. Your list will be the bloodline of your business.