Members like the Chat/Shoutbox too much? Can't get them to post?

[Drocr]

Okay, well since I have had the shoutbox on my forum for over a year now, the shoutbox has always been one of the annoyances of mine that just drove me insane. My members like it.... almost too much, they don't want to be bothered to go through the forum and post when they can just talk about what they want in the shoutbox. I have tried several ways to encourage posting and decrease the insane amount of talking in the shoutbox such as: Don't post, the shoutbox goes. That worked for a little while, then they went back to not posting much again. (Mind you not all the members are like this, just a lot of them). I have also tried: 20 posts to view the shoutbox, but then it just stopped new members from posting in the beginning, and the older members were still on the shoutbox. So... what I think can solve this, or at least help make the shoutbox more useful to the forum and less destructive is this:

Can someone make a shoutbox that controls the amount of time a user can be on it. Such as daily or weekly. But even better what I am really hoping for is for someone to be able to make a post limit per day/month that a user has to reach before they can view the shoutbox.

Let me know what you think, thanks in advance!