Ask HN Designers/UI Folks : New Project Design Challenges

Folks, I am getting started on a new project a social tool. I am working on the design and ui theme for the web app but hitting some virtual wall. Most of the new ideas I am getting, seem to be copy of friendfeed or twitter or another popular web site. Please help me on how should I approach this so I have a unique look and feel with a different webapp personality.

I am resubmitting this from my earlier thread, as due to time difference my thread go lost and I really need help.