Find me some Leads

Hi, I have plans to create a website like oDesk or elance. Before doing that, I have real questions to ask from you so please answer them while bidding. 1. okay reason to create this kind of site is to get your share and there are very less famous website, oDesk, elance, freelancer, vworker, peopleperhour, that's all i guess, if we talked about famous for sure.. So, it seems there is less completition and agencies love to create their account on multiple freelancing websites so they can get more bussiness. Now real question this all we know then why everyone is not doing that and making the money ? 2. How much it cost to do a best marketing to get this idea functional, in short, i just want my website on top of the list like oDesk, elance or freelancer, so what's the cost ? 3. what are different marketing methods to achieve this goal? 4. What are the risks for this business even if I invest the proposed amount. I mean best case and worst case ? btw, I just need marketing not development. Thanks. goni