I don't mean the design of the code, although that's a little bit of a mess as well. I mean - Your site and Stack Overflow share some functionality, but they do not serve the same purpose. You've basically taken the Stack Overflow design and layout and copied it. Your design cannot work unless it comes from a single purpose and central idea. This applies for everything, not just your design. Features and functionality, as well as design, cannot work unless they follow from your that single basic idea.