Knowledgebase
How to disable and enable the newsletter feature in Magento
In Magento customers can subscribe to your newsletter. The newsletter subscription function is enabled by default. Customers can sign up for the newsletter while creating an account, registered customers can subscribe from their account settings, and guests can subscribe from the Newsletter block displayed in one of the columns. If, however, you don't want to send newsletters and you want to disable this function you can do this from the admin panel of your Magento.
To do this, log in to the admin panel of your Magento and go to System menu>Configuration>Advanced button in the Advanced section on the left. Expand the Disable Modules Output panel on the right and set the Mage_Newsletter drop-down menu to Disable. Don't forget to click on the Save Config button in the upper right corner. This will automatically remove the newsletter subscription options from the frontend of your site.
If you want to enable the newsletter function again, just set the Mage_Newsletter drop-down menu to Enable.