Sometimes it may be good to show somethink to user.
This script can do it.

Instead of lime we put space from right in pixels. The best value - 5px;

Instead of yellow we put space from bottom of screen, not of all forum! The best value - 20px;

Instead of 2px dotted #FF0000 we put:
First value (2px) - size of border in pixels
Second value (dotted) - type of border, all types here are:

Third value (#FF0000) - color of border;

Instead of aqua we put background color;

Instead of purple we put text color;

So... Instead of "your message" we put our message. We can use HTML.

You can put this script in any place of forum.
But the best variant is:
First script block (from <style type="text/css"> till </style>) put in HTML-header. Other blocks you may put in HTML-footer or in announcement.