Yes, each list is saved to a specific list category. These help you to easily identify lists that you should send each campaign to. You can set the category when you create a new list or when you edit an existing list. This category will be what your recipients see when they subscribe or unsubscribe to your email communications.
To edit the list categories, select an email list from the Contacts Page in the Email Marketing Module. Click on edit in the bottom right corner of the light blue box. This will open a new dialog box. Click the arrow in the Category box to open the list. Click on <New/Edit> to edit the category list.
You can add new categories by typing into the empty box at the top of the list, then click on the save disk icon to the right of the box. You can also make a category private by clicking on the lock icon to the left. A green open lock icon indicates the email list category is publicly viewable and a red closed lock means that the list is private and not viewable to the public. Be sure to click on the save disk icon on the right to save your changes.