It's easy: show me the code. Links to quick examples and tutorials that show me what and how this language can do are amazingly useful. Pretty much you want the primary focus to be on using your language, not selling it. You have a navbar across the top; at first glance I know for 100% certainty only what two of those links will do for me ("home" and "company").

In short, look at http://python.org/ , http://www.perl.org/ , and http://www.ruby-lang.org/en/ . Focus on enabling the developer to do something useful as soon as possible. Focus on community, libraries, etc... If you make one change and only one change to the site, add a link titled "Getting started"... make it a wiki. See http://www.erlang.org/starting.html for more inspiration. Right now it feels like the marketing department designed the the cilk site.