This suggests that a brand makes a promise to somebody and they attach some value to it. Yes, that promise might be interpreted differently by each person and the value they attach to it might be unique to them, but marketers can shape the way they wish that value to be perceived while striving to promise something unique.

The brand is the unique promise of value attached to some entity while “branding” is the process used to try to communicate that promise and attach it uniquely to the product or service.

A primer at:
http://www.davedolak.com/articles/dolak4.htm