They mentioned, just before this talk, that there are 6,000 people in the first room. edit: I guess I misunderstood, but it's still impressive that they filled the place up after just 2 years at this conference center :)
Actually, it was "6000 people at this site, today" -- he wasn't very clear. I think they're expecting another 2000-3000 to show up over the next days at least, making it biggest CCC ever by far. I'd estimate more like 1-3k in the room itself.
In my experience it's enough to version control custom parts of wp-content (you theme, your un-published plugins) as everything else is better left to Wordpress one-click updater.
