Post to all your social network sites from one location all at the same time which ideally drives targeted traffic to all of your content.
Join and learn from others in the community. Cross market. Help each other succeed. Find new friends that have same interests.
Every thing you need to have a fully functional search engine friendly website and more. Drive targeted traffic to your content.
Use your own domain name if you want, or settle for a subdomain. Either way you will have the same marketing tools in the network.