If a real-world company is renowned for being a great destination and a comfortable place to shop, that quality may not transfer to the web. People may associate the company not with the category of product, but as a place to go . A brand doesn't help the user add an item to his shopping cart, it doesn't help him figure out his shipping options, and it doesn't help him get through a web site's commerce track any faster. A brand helps the user authenticate the supplier based on past experience with that brand in a different context, or based on reported experiences of others with the brand. I will look for that company online because I respect the brand .
Brand helps users identify the product and or company behind a product.
The simple truth is that employees represent their company, and if I go to my neighborhood Best Buy to pick up some software, I deal with a salesperson. The customer's experiences with a company form the basis of the brand's connotations. When I encounter the Best Buy brand, I recall a very definite expectation of the caliber of salesperson and their level of training and product knowledge. We can't ask the person behind the register about their day, we can't flirt with the person straightening shelves, we can't share in the dynamic between other customers and sales staff. We can gather not one iota of conversational information from an online site, because a web site represents itself.