I've added a Search feature to the shoutbox.
You can use it by going to the
shoutbox archive (normally you would reach this page by clicking View Archived Shouts in the top right hand corner of the main shoutbox window). It's on the right hand side.
Please test it out and report any problems here.
Also, archived shouts will be kept for 72 hours from now on, as opposed to 24.
I may at some point also devote some time to making it work in Safari (browser of choice for many Apple Mac users, for you Windows people), as I imagine its state of being compulsorily disabled annoys them slightly...