When the newsletter module is enabled, customers have the option to sign up for your newsletter. When the module is disabled, they cannot opt out of the newsletter. Instead, they are automatically added to the newsletter subscriber list.
1. Log in to your site's backend or Administrative Panel.
2. Select System | Configuration.
3. From the left menu bar, select Advanced.
4. For Mage_Newsletter, select Disable.
5. Click on the Save Config button.
When someone creates an account on your site, they will automatically be added to your newsletter subscription list. They won't be informed about this, and they will not have the chance to opt out of receiving the newsletter. Before doing this, check the laws in your jurisdiction. Some places require you to inform your readers if you subscribe them to your newsletter. Disabling the Mage_Newsletter setting removes the checkbox that you saw in the previous screenshot: