The importance of colour in branding . . .

First, let's address branding, which is one of the most important issues relating to colour perception and the area where many articles on this subject run into problems.
There have been numerous attempts to classify consumer responses to different individual colours: ... but the truth of the matter is that colour is too dependent on personal experiences to be universally translated to specific feelings.
But there are broader messaging patterns to be found in colour perceptions. For instance, colours play a fairly substantial role in purchases and branding.
In an appropriately titled study called Impact of Colour in Marketing, researchers found that up to 90% of snap judgements made about products can be based on colour alone (depending on the product). And in regards to the role that colour plays in branding, results from studies such as The Interactive Effects of Colours show that the relationship between brands and colour hinges on the perceived appropriateness of the colour being used for the particular brand (in other words, does the colour "fit" what is being sold).
The study Exciting Red and Competent Blue also confirms that purchasing intent is greatly affected by colours due to the impact they have on how a brand is perceived. This means that colours influence how consumers view the "personality" of the brand in question (after all, who would want to buy a Harley Davidson motorcycle if they didn't get the feeling that Harleys were rugged and cool?).
Additional studies have revealed that our brains prefer recognizable brands, which makes colour incredibly important when creating a brand identity. It has even been suggested in Colour Research & Application that it is of paramount importance for new brands to specifically target logo colours that ensure differentiation from entrenched competitors (if the competition all uses blue, you'll stand out by using purple).