kwrited does not work out of the box and I could not get it to work ever! I read something on a debian mailinglist that it was disabled for the sake of security and I guess therefore it is not working in ubuntu as well.
However, I would find this daemon very usefull for sending system messages to all logged on users (e.g. messages from a UPS).
I was hoping I could use it for that, but since I never got it to work, I can't really tell, if it is the right tool for the job.
If you know and think it is not, maybe you can come up with some other solution to deliver messages to all logged in users. Such a thing is especially important on thin client systems, where you might want to warn all users that you are going to restart the xserver in 10 minutes.
This is not to happen in Dapper, and if Debian chose to not activate it for security reason, I don't think we should activate it either.
Note : when you want to inform all users of a shared system that you're going to shutdown/reboot, you can use the -t flag with the shutdown command.