In one word (with punctuation): SPEED!! The same lesson can be learned through Reddit.com. When I vote for content on these sites, the response is virtually instantaneously. Same thing is true when I navigate from page to page and add people as friends.
I love using Digg and the design is pleasant, but the slowness lately has been dampening the fun factor. I’m tempted to install some type of ad-blocker or edit my hosts file, but I want to continue supporting their efforts.
Digg, if you are listening, please speed up your system. We will all rejoice.