Build Your Own Community

An abundance of 'build your own' social network platforms has recently surfaced due to massive success gained by Ning. Wackwall is another free social-network creator that allows you to easily customize your network in easy steps. It even allows you to use CSS coding to give it a great visual feel and to map your domain name instead of having something along the lines of 'mynetwork.wackwall.com'. Although customization of advertisements on your page will require a premium package from Wackwall.
It's a startup now, but I expect a lot of upcoming traffic on Wackwall as people build more niche communities tailored to their specific interests.