Very impressive. Thank you for the incredible write-up. I got a whole bunch of ideas for my own business's network architecture while going through your post as most of my needs match up with that of yours, as you elaborated in your post. Can't wait to post back the results post-implementation.
I disagree. Reddit has done a good job of branching itself out across various diverse communities, and has been experimenting with geographical location based customization among other things which I feel should be enough of a buffer against going down Digg's path.