A registered user is one who uses a program or a website and provides his/her credentials, effectively proving his/her identity.

Generally speaking, any person can become a registered user by providing some credentials, usually in the form of a username (or email) and password. After that, one can access information and privileges unavailable to non-registered users, usually referred to simply as guests. The action of providing the proper credentials for a website is called logging in, or signing in.

Since the site knows about the identity of persona using the page, it can:

Registration has many disadvantages for web users.

Registration is effectively a backhanded way to allow cookies, something most users try to avoid. In many cases, it even mimics third-party cookies. Once one has registered for a site, it can effectively store the browsing history on its own server where the user cannot delete it, and it can also share it with other commercial databases.

In fact, gathering personal information on users is the main reason that some websites require registration.