Shoutbox would allow to edit in the backend the messages that were added through the Add Shout button or even those added by members. Let's suppose we want to fix a text or remove a bad word.

Yup, I'll have to agree. That makes sense. Ok, so instead of allowing to edit, it should allow to add a new one. Let's suppose you want to use the shoutbox as a news scroller instead of a shoutbox. So, it would hide the buttons from the users and the Admin would enter the news in the back-end. So, with one component, you would have two tools. I mean, use it in one way or another. Well, just a suggestion.