When a user subscribes to your mailing list, he or she is sent a confirmation email to make sure it was really them that subscribed, and not someone subscribing on their behalf. To prevent abuse, the content of that email is not customizable (however it is automatically translated into the recipient's language). You can, however, add a short text message to the confirmation email. Here's how:
- Switch to the Addresses tab and select the group that contains your subscribe form
- Click Edit Form to edit your subscribe form
- Switch to the Options tab
- Check the "Confirmation email message" checkbox and enter the brief message you'd like added to the confirmation email.