Social Networking Website Development

We need a clone of [login to view URL], but would target the "shopping" topic like I want to buy a "product". Please familiarize yourself on how [login to view URL] work. The script must fast, does not take up heavy server resources and must be SEO optimized like 43 things (meta tags and titles of each page). Private messaging must be in place as well. You or your company needs to be good in programming and designing. We need fast loading pages for the design. Not too much graphics, css based, and must be compatibe with the leading web browsers. You should build this script from the ground up and not use/modify existing script(s) which are currently available for sale in the web. Website maintenance will be awarded as well if everything goes well with this project. We need a team who can communicate very well and provides regular updates.