At least when it comes to internet culture, it's where a lot of stuff originates these days--- the same jokes and memes will eventually filter down to digg/reddit/elsewhere a bit later. Sort of the role that SomethingAwful, Fark, and digg have played at various times, to various extents.

That's community, not tech innovation.

Sure, but digg (like most social media companies) has always been more about innovation on the social side than on the technical side. The actual technical meat behind digg or twitter isn't what made them successful; finding a way to make themselves the center of certain kinds of culture is.

Innovation is what happens when you take the friction out of a community.

moot can't really build much on the platform he adopted from 2chan. He's probably going to innovate in the web community / imageboard space with his new startup Canvas.

Well they added Captchas recently, if that counts. I suspect it doesn't.