An unregistered user of the site is commonly known as a guest or visitor. Guests are typically granted access to all functions that do not require database alterations or breach privacy. A guest can usually view the contents of the forum or use such features as read marking, but occasionally an administrator will disallow visitors to read their forum as an incentive to become a registered member. A person who is a very frequent visitor of the forum, a section or even a thread is referred to as a lurker and the habit is referred to as lurking. Registered members often will refer to themselves as lurking in a particular location, which is to say they have no intention of participating in that section but enjoy reading the contributions to it.