A community implies social link, emotional engagement, and above all, a degree of ownership. A community member is an owner & a contributor, and the product is part of their identity.
This is why community members will go to great lengths to evangelize your product -- allowing you to grow faster on a $0 marketing budget than your big corp competitors that spend millions.
A community is an incredible growth vector and an incredible moat.
The community isn't a tool that you use to build a product or company. The product or company is a tool that you use to build and sustain your community.