Shoutbox

A shoutbox, saybox, tagboard, or chatterbox is a chat-like feature of some websites that allows people to quickly leave messages on the website, generally without any form of user registration.

In their simplest form, shoutboxes are simply lists of short messages, possibly with information about their authors. The page may be automatically refreshed after a certain interval, or polled dynamically in order to keep new messages visible. Older posts are often deleted after a certain number of messages have been written in order to preserve space on the server.