Not much to do with content, but some sort of syntax highlighting (even just bold-facing keywords or something) would make longer code samples on such a site much more readable -- both for Arc and Scheme snippets. At least to me. There's still the sect of people who are too manly for syntax highlighting or whatever, so you could have a link at the bottom of codeblocks to toggle it.
This also applies to inline fixed-width fonts, which you should have as well. It's annoying as hell to have a billion conventions for inline code here: some people 'quote, others "quote", you could italicize, some don't do any formatting, and sometimes I just get lazy and put it
in its own block.
A sane syntax for this would be good. I'm never sure if arc-globals* interact well with the italicizing syntax (asterisks) in different contexts: (= global 5)*?