Welcome! It's good to see more people with an interest in Arc.
As for your questions:
1. The best way is to do (thread (asv)), which will launch the server in a separate thread. Then, to modify it, just (load "blog.arc") and refresh the pages.
2. No idea :/
3. As far as I know, it doesn't---but there's been remarkably little spam here. I'm not 100% sure of this, though; I could well be wrong.
Also, I recommend using Anarki instead of arc2.tar. It's much more actively developed and has a lot of really nice features. There's more information at http://arclanguage.org/item?id=4951 .
> 1. The best way is to do (thread (asv)), which will launch the server in a separate thread. Then, to modify it, just (load "blog.arc") and refresh the pages.