A community goes beyond simply the group or number of people experiencing your brand on their own. It brings them together in one place for a shared experience.
An online community can generate new leads, improve customer retention, add value for your existing customers, and give you deeper insight into who you’re talking to. Your audience is merely a part of this.
Good break down of how bilateral engagement is what makes a community a community with a few examples of audiences (unilateral engagement) vs communities (bi-directional engagement)