MOTDstripper strips the guild and system message of the day from your chat frame, freeing up precious screen real estate and making your chat frame cleaner upon logging in to the game. Messages of the day are only shown if they've changed since your last login.
You can change MOTDstripper's behavior through the AddOn Options in-game. By default, if MOTDstripper has seen either the current guild message of the day or the current system message of the day (or both), it will strip them from your chat frame when you log in to the game. Messages of the day only show up if they've changed since your last login. The AddOn Options menu allows you to specify which one of the two messages you want stripped. Options are saved on a per-character basis instead of globally for all your characters.
In case of new features please note that I'm not particularly inclined to add unnecessary bloat to the add-on. Features I'm considering are pop-up notifications upon changed messages of the day and being able to review past messages of the day. One thing at a time though, don't hold your breath.
The add-on is in its testing phase. At least on my machine it gets the job done. However, while it is unlikely, the add-on may very well melt your computer or show other unwanted behavior.
You can always find the latest alpha versions at the MOTDstripper WowAce home page where I maintain the add-on. Alpha versions may melt your computer even faster than beta and stable versions.
If you can, please review the source code and point out any obvious mistakes I made. For me MOTDstripper is a means of applying what little Lua knowledge I have to a real-world project. I'm fully aware that the source code must have plenty of room for improvement. I'm willing to learn and I'll gladly accept any hints you can provide.