I want to build a highly secure social networking portal. Like other portals, subscriber users should be able to create a topic, discuss topic, share information about them, and have the ability for notifications/alerts. The added feature, I would like to have is to moderate users. Based on the topic of discussion, users will be asked automated questions and their responses will be processed to provide recommendations. I have no knowledge of social networking portal requirements. I will be coding alone and want to have something up and running in about six months. Which is the easiest open source platform that I should use to develop? I know some.net and sql, but I am open to use other platforms. Please give me your recommendations