In our era of mass communication, mass mobility, and mass differentiation of personal attitudes, beliefs, interests, and philosophies, communities are no longer geographically bounded entities. They are communities of shared experiences, shared beliefs, shared activities, and shared ideas.
Communities grow up quite naturally.
You naturally gravitate toward people who share your outlook on the world. Who like the things you like. Who want the things you want. You share ideas, thoughts, and feelings with them, and they become your friends. We all need these communities as part of our lives.