A subscriber may refer to a user role in WordPress. Usually the subscriber user role has very limited capabilities. Unless the default capabilities are changed, the subscriber user role is the most limited out of all the WordPress user roles. They can create and maintain their profile on a WordPress website, but they can not write or publish articles. Because they can login to the WordPress dashboard and make changes to their profile, this means that they have a very limited ability to modify the WordPress database. Just like with the other user roles, the default abilities of this role can be modified.
With default settings, the subscriber role allows users to login to a WordPress website and leave comments without having to enter their details every time. This role is useful for people who frequently read a blog and are actively commenting. It can make leaving comments on a blog much easier and faster. The subscriber role can also be used to deliver additional content to users such as newsletter or access to the pages and posts that would otherwise be locked.
Subscriber may also refer to a user who has subscribed to a website using an RSS feed, mailing list, or any other feature to receive updates from a website.