Very cool! Kashif just emailed me about a dev project at Wordpress.org for a multi-user version! That's pretty awesome - I didn't know it existed at all! And it looks like it's stable enough for real use - Blogg.com is claiming 989 blogs at the moment and there's a bunch of "city blogs" in Australia that are using it as well. This is *very* cool. I especially like how the URLs are automagically made with an extension to the domain name like russell.blogg.com - very clean. And the setup process is all of three fields and an email confirmation. Wow.
Now, I have to say, I would be a bit hesitant to put this on a public server just yet, as there's lots inside of WP that works for admins in a pretty open way. Check the WP documentation for stuff like "just chmod 777 to make it work" which makes me a bit wary about opening up my server to the multi-user blog stuff just yet - not until it hits 1.0 at least. But for internal blogs like at work? This will be awesome.
Cool-ass discovery. And don't be fooled by the public site, I was wondering how current the project is, but I just checked the change logs and there's work continuing up until today, so it seems very active. I hope they keep pushing, as this is something I think is very cool.
Update from Matt:
MU is the software powering WordPress.com, with 116k blogs and counting. We open source almost all of our code, and lots of hosts are using it.
[Andrew Watson] maintains a list in his sidebar of sites using MU to provide blog hosting: http://andwat.edublogs.org/
That said, MU is really intended for a more sysadmin-type audience.
Nice. I also noticed (by checking out Andrew's site) that there's a new entry in the Codex about WordPressMU as well. My response to Matt was something like "Why haven't I seen this before?!?!"