A prioritizing and branding tool.The concept of the Purple Cow was introduced by Seth Godin in his book by the same title. .When you drive by a heard of cattle they all look like cows and it doesn"t seem out of the ordinary. But if you drive by a heard and standing in the field is a Purple Cow you have to tell someone because it is so different. When something forces you to remark on it, by definition it is remarkable.