1. Start with the minimum viable product and expand your idea from there. It is really hard to improve a product if you don't know where to start. Radically slim down your app to do and show only the bare neccessities, the core, the meat of your service. From there, you can always slowly start to expand the feature base as long as you remember that it will never be the extra features that get you your users, it is the core that matters.
I strongly suggest you to(at least temporarily) remove: Display of people online, all the sorting buttons, the red in yellow notification, the need to sign up or login, the amount of views per post. Next to each post, only show amount of viewers, don't discriminate between guests or users.
After you have done this, start working on color-schemes, and read online guides on typography to make the interface less confusing and complex. Make sure a visitor's eye is drawn towards important elements, and that less important elements are in the background more ( smaller, less bright typography/elements).
2. If realtime Digg is not unique, why create one? It doesn't matter if it's unique or not, as long as your users get what you are offering them. "Interact with Others" is a slogan that could apply to
an alcoholics anonymous group or a dating website. What does your website do that is appealing to me, in a maximum of 5 words?
3. Your first and foremost concern right now is to get users,
if the site gets too chaotic- at least it will be used.
In the event that you start to get serious spamming issues,
you are most likely successfull already and you will have plenty of time to fix the problem.
Don't think that far ahead.
Cheers,
-Edo