Doug Stewart started the discussion on using WordPress for user-generated collaborative websites. Some ideas were thrown in, including the usage of TDO Mini Forms plugin to help the job.
Mike Schinkel found out that an archive page for a month with no post returns an 404 error. Discussion followed.
Malaiac asked: What is the oldest available file in WordPress (meaning that the file existed since the earliest version of WP)? And it seems like the /wp-admin is the answer (MichaelH also pointed to a really old, WP 0.71 zip file for further checking).