There are lots of ways to create a social network that involve scripts and paid hosting, and all sorts of settings that you have to get right before you can get your network up and running. If you’re looking for a way to skip all of that, and get right to the good part – customizing your social network and inviting your colleagues and friends to join, there are two free and easy ways to do that.
http://www.makeuseof.com/tag/2-easy-ways-create-a-social-network/