The issue here (no matter how big your list is), is how do you get them to open all of your emails or at least most of them? If you look at the response mailing list rates of 95% of all internet marketers with a list they have manually built, the response rates never go further than 5-12%. How so? Why do people discard your emails into the trash folder without even opening them?
It happens because people are just tired of getting pitched to. People hate receiving spam, "great offers", "once in a lifetime deals" and so on... Admit it, even you hate it, everyone does. If I had a nickel every time I have deleted an email without even mailing list opening it up, I would be 224.5 million dollars richer. What you need to do is to think of a way to make the person WANT to open your emails.
You need to figure out how to make people sit there, refreshing their inbox page, eagerly awaiting your messages. There are two key principles you need to follow in order to build a responsive internet marketing list. What you need to mailing list do is this: provide value and be consistent. First one is obvious. You need to be providing value to your subscribers.