For me, the best way to think about a brand, especially for a startup, is ‘what are people saying and thinking about us’.  (This relates nicely to your recent excellent post about understanding how customers would describe your startup.)  Thinking about it this way focuses the ‘brand owner’s’ attention on several important points– on how people will probably only understand or repeat the most highly salient points about your company, about how anything you say or try to convey about the brand is interpreted through the lens of WIIFM, about the need for consistency between your business model and your brand (as people won’t believe brand messages that are not in harmony with your business model.)

In technical terms the receiver’s point of view is the ‘brand image’ and the sender/marketer’s take on the brand is the ‘brand identity’.  But in the world of getting traction through a tribe’s enthusiasm rather than based on a bunch of one way messages somehow getting an audience’s attention, spending much time thinking about the latter in isolation is just not efficient. 

Best
Chris