It's an "unofficial" channel. The main purpose for it is so that I don't get accused of flooding #phpbb or #phpbb-mod. However, you'll notice that I haven't taken the time to set it up properly or anything. Furthermore, I often forget during the show to look at it very frequently--it's hard enough to keep an eye on the TalkShoe chat room, however I do try to keep #phpbb-weekly and the chat box on Star Trek Guide open during the episodes, but even then, their activity has diminished since TalkShoe recently released their web interface.
So, I'm not sure about what will happen with #phpbb-weekly, but for now, it's just an "unofficial" channel for whatever.