Why is colour so important when discussing marketing/branding? The use of colour when focusing on aspects of marketing and branding can be a very interesting strategy to choose and determine how effective it will be long term.
Colour is so personal, from the choice of colour, that if you are a fan of a certain colour you can relate to that brand and/or marketing strategy more so than if it was a colour you were not a fan of. So the idea that a colour such as yellow or purple can conjure up an emotion that only you can relate to is the goal of every marketer and organization setting a colour to a particular brand.
And it is this type of strategy that successful marketers and organizations achieve by researching the type of target audience/market they are going after. In some cases, colours are preferred based on their own preference and trends, but it is the successful ones that choose a colour that can take that campaign and brand to the next level. That is the science behind how to differentiate between a successful brand or non-successful brand.