Networking + online forum website

Hello, I would like to build online forum website with following features (more will be discussed later): - Anybody can register. - Should have following and follower feature like Twitter. - Registered user would have one share link to put quick note to share with follower or follower’s follow etc. (like we have in facebook) - User can put articles that also can be shared with others. - Quick note and article will be posted under category or categories. - Website should support plug-in type feature where any part (architecture and page reason) can be replaced easily without any technical help. - The look and feel of website should be very light weighted and profession like take an example from [login to view URL], [login to view URL] (very clean and no quiz to find option) - The bidder will be required to prepare the Requirement Understanding Document, System High Level Design Document, System Architecting, Designing, Development, and testing. -The system should be developed by implement industry best practices, patterns, and practices. - Web Application should have best performance and should require minimum round trip.