1. Not sure what you mean by "organized." If what you mean is giving access to specific members to specific categories or pages, then you might want to use a separate plugin for this, such as "Groups" and "Group Restrictions":

wp-group-restriction - Google Code

2. I didn't design that theme. It was designed by Cory Miller, based on my blog's theme (which I did design myself). It's just a preference. But if you want to find out why (or more), see:

Cory Miller Media | Blog Design & Custom WordPress Themes