It is possible in some guestbooks for visitors to express their thoughts about the site or its subject. Generally, they do not require the poster to create a user account, as it is an informal method of dropping off a quick message. The purpose of a website guestbook is to display the kind of visitors the site gets, including the part of the world they reside in, and gain feedback from them. This allows the webmaster to assess and improve their site.
Often, e-mail addresses, the visitor's site's URLs and IP addresses are collected, and sometimes published. A guestbook is not intended to be a place for discussion. Due to this, a guestbook is different from a chat room (which is more or less realtime communication), or an Internet forum (which is intended to be a location for discussions), or a blog (which is intended for regular updates and more involved exchanges).