I do get that people are using the shoutbox (instead of the forum, or other platforms) to discuss the usual drama /ingame issues/etc. It's there because people asked for a place to chat while ingame, an IRC channel was discussed but the shoutbox was created instead. If you look at the whole wall of shouts you will notice that its limits are mostly due to the amount of people (both the forum users and the players) that can post shouts on it.
On the other hand, i just took a look at the shoutbox and i can still see shouts posted 8 hours ago. That is quite a fairly decent amount of time, even with the discussion that went on during the night.
hey
what about that:
after 100 words per day writing to shoutbox, you are banned for 2 days on it.
ok, maybe 200 words 
200 words would roughly mean...not more than 7 or 8 posts by average, unless you make 5 to 10 words shouts, honestly barely enough for a statement.