As a Crohn's sufferer, It's rare that I come to HN and see something so closely targeted to me! One thing that makes me a bit nervous, though, is the social nature of the site. I tend to be pretty private about my illness, and only my closest friends know I have it. Have you considered the privacy implications of the site? I'd be worried that information about me and my condition might leak onto the internet, and the homepage doesn't really mention it.

I applaud the effort, though. Crohn's is a terrible disease and it's great to see people taking proactive steps towards treating it.