Q2A is a bit of a mixture at the moment. It was originally created using procedural code and it's mostly still that way. However, I am trying to move it towards an OOP style. It will take a few versions to get there, since any major changes would break all existing themes/plugins.
It's not clear exactly what you're trying to ask regarding your social network site. Are you using the Q2A platform to make it, or doing it from scratch?