Community
People truly caring & engaging with the brand
Community is what happens when people stop being customers and start being part of something together, and that shift changes what a brand can do.
A community around a brand is not an audience that happens to be in the same place. It is a group of people who feel a shared identity, exchange something of value with each other, and would notice if the brand disappeared. That is a much higher bar than having a large follower count or an active comment section, and most brands that claim to have a community actually have something far thinner.
The brands that build real community tend to do it by enabling connection between people, not just between people and the brand. They give members a reason to interact with each other, a shared language to use, and a sense that belonging to this group means something. This is harder to scale and harder to measure than other brand metrics, but when it works it creates a defensiveness that advertising cannot buy.