My theme is a standard third-party theme that's installed through the WP admin interface. But all themes as I understand it are PHP code (emphasis on code), not something in my database. So I was wondering just how it would work. I guess I could just set up a new blog and see how things are put together.
I'm also concerned about plug-ins. My blog would be unusable without some kind of anti-spam. I use Akismet which has so far blocked over 50,000 spam comments.