Chances are, if you're using Constant Contact for your ezine, you have THEIR logo with a little "try it free" phrase on the bottom right of your ezine.
Want to increase the professionalism (and appearance) of your ezine?
Simply email their support (from within the Help & Support menu) and ask them to remove the logo from your account.
After all, you want your ezine to brand YOU, not your ezine service provider. 🙂