The biggest difference is this is a competitor to traditional news (New York Times, CNN) and not digg and reddit.
I believe we are going to share some of the mechanics that drive digg, but where this is very different is when you view story it is not a link to someone else's content - the content lives within the context of the site.
Also I will say that the idea is not fully formed yet and needs some more thought. The biggest problem is how the content gets curated and how it gets seeded.