Ideas cannot be protected. They are also very much common. I suggest you build a very strong business case for your proposed website, including things like looking at revenue sources and cost for hosting for the first year, as well as a good analysis into other social networks and how yours will be distinguished and prosper, before investing any additional time and money into your idea.
I don’t mean to discourage you here, but ideas are pretty much worthless, everyone and their mom has an idea and I can guarantee you someone has had your idea before. What matters more is whether it’s a viable business opportunity, and to prove that you need to do a lot of research.
As a professional web designer, I have zero interest in your idea as presented here. What I care more about is whether it’s a viable business, whether my investment of time and energy and money will have a result that directly benefits me. I need to see your drawings, your ideas, feedback you’ve gotten when talking to others about this idea, etc.
For instance, here’s a first question – why would anyone use your site instead of Facebook?