ergophobe - 4:33 pm on May 3, 2010 (gmt 0)
No need for apologies... we welcome all questions and you're ahead of me in testing WP3, so good for you.
I think part of the hoopla is that for the last few versions of WP 2.x there's been talk of a merge between WP, which in its origins is a personal blogging platform, and Wordpress MU, aka Multi-User, aka WPMU.
The problem has been, for example, that some WP themes and plugins didn't work in WPMU and some did, so if you wanted to use those plugins and you wanted to run multiple blogs, you needed to have multiple installs.
With WP3, there's a full merge, meaning that WPMU has ceased to exist and WP now has multi-user, multi-blog functionality integral to it.