A brand is the expression of consumers equity in a product offering. This offering is a mix of tangible and intangible factors, a bundle of benefits, each being inter-related to the others in ways that may vary depending on the differing consumers.
Brand strength = Differentiation x Relevance of the differentiation.
If you apply this formula, it may help in the difficult task of making the choices relating to which customers, which channels, which media approach, which opportunity to follow, which brand to invest more in, and so on.
It may also help to add some numbers to the often qualitiative marketing strategy dicussions, so the CFO can understand what you are doing, and why you are doing it. This is normally useful in a corproate environment.