Corporate identity is the face and the interface of your brand. It's about the look, feel and visual elements of your product, so it must articulate what you want your Brand to be. Uniquely tailored to your positioning, your Corporate Brand Identity must be uniformly conveyed across communication channels (internal as well as external) and stamp all your marketing collaterals, at all consumer touch points.
So whether it is a letter head, a stationary deck, a banner ad, a signage, a print ad or an online tool, 360 degree communication of your corporate identity is absolutely essential to establish a strong presence for your brand in a cluttered marketplace. It's a short-form of your brand, and a positioning statement.
Without a well-differentiated corporate identity design, you are another product not a brand.