Users of the Princeton University MT blog server no longer have to type blogs.princeton.edu/exampleblogaddress to get to a blog. You can now just type blogs.princeton.edu/exampleblogaddress. If you are on campus, that address is just blogs/exampleblogaddress.
To get to the admin interface, one can instead type blogs.princeton.edu/mt. You may have to log-in an extra time until your browser cookie is set to the new address.
All of the old addresses still work (ex. communitas/blogs/, commons/blogs/, communitas/mt3, commons/mt3, etc. Old links and bookmarks should seamlessly redirect to the new addresses.
A site rebuild will change any addresses in your blog that are generated by the <$MTBlogURL$> tag. Any absolute URLs in any existing posts will continue to work. Manually changing them is not really necessary. Any new URLs generated by Movable Type will use the new address.
blogs.princeton.edu, by itself, just goes directly to this site.
www.princeton.edu/~blogs also goes to this site.
The communitas/blogs directory is no longer browsable. However, I plan to replace that functionality with a PHP-generated directory browser that will enable exclusion of certain files and directories.

So where can I get an index of all publicly available Princeton blogs?
I have been wanting to provide such a list ever since I took over the blog server, but have not yet had a chance. I hope to have a proper index some time this month.