Customer communities allow you to give your customers a place to build bonds and share experiences. Give your brand advocates a place to hang out, to talk about their experiences with your product and other interests. They'll form connections within the community organically, and strengthen their connection with your brand. Customers that feel valued come back, buying more and more often than from brands with which they have no affinity. Everything hinges on the social aspect; it's what gives customers a reason to return, to give support and to sing your praises to their friends.