I just updated my site since I was curious as to how the updates would work. It worked quite painlessly. However, when it was done it asked if I wanted to update all the sites as well.
I was under the impression that the multi user capability was sharing the same codebase and db amongst all the sites (not that I've done any research into that, just that I don't see any subdirectories anywhere for the subdomain sites).
So, if they are sharing code and database, what exactly needs to be updated in the network sites? Or am I off base in assuming that they are sharing all the code?