This is neat. I always thought a hosted reddit/HN solution would be a good startup idea. Imagine a site where I could start my own reddit/HN type space with a unique url. I could then control who comes in (be it co-workers or friends) and have a place where we could all privately share links and start discussions. Great for companies, project groups, families, friends, etc...
I know I won't have time to build this, but I think somebody should.