I feel that if one is attempting to reinvent Facebook, that is the wrong route to take. Zuck caught some luck and Voia! Facebook. However, it's important to focus your energy on something you love or are truly interested in. Build that niche and keep the community interested with quality data and they will spend their time there. Nothing needs to be moving all around like back in the day of macromedia flash and you don't have to have so fancy of an interface...people want simplicity and responsiveness. If one can build a solution offering interesting data that is formatted and works well on any device, your community will undoubtedly grow exponentially.