In their case, the archive reflects useful reference material that has ben churned up in discussions or even single posts that contain valuable information. Much of that site is, of course, focused on technical knowledge and so, in their archive board there is a child board of key postings that come from the microphone forum and a child board with key posts from the pre-amps 7 processors board etc.
For week4paug, I see it as this:
-Phish reference materials
-definitive *blah* list threads. (this stuff probably becomes irrelevant once the wiki is live)
- technical help
- how to bt
- how to convert x to y
the idea being to keep old stickeys and other threads that may no longer need updating in an area that is even easier to find than wading through search results.
Perhaps, tho, it's not needed here.