SBW was created because people kept whining that BigWigs didn't have the auto-reply stuff while fighting bosses that some other boss module addons do. I just got so sick of hearing that this belonged in BigWigs and that we should add it, so I had to create this little addon to show people that it can be done easily without hooking into any sort of boss addon framework.
The code is very simple and just works. There are no config options and no UI.
Install it, and when you're in a boss fight, people who whisper you (as long as it's not a GM and they are not in your raid group) will get a reply saying how many % the boss is on and how many people are alive.