@rb, I buy Coke because it tastes okay, it contains caffeine, and I have some fond childhood memory attached to it. But it is not something I will miss much if it disappears tomorrow. I did not buy the stock. This is about my understanding of Buffett's literature.
@Seanzy, thanks for the thoughtful response. So it is about brand loyalty, which is group psychology, which is mysterious. A brand gives consumers some unique expectations of the product or service. But how do we know what brand will have loyalty and what brand will not? Brand in printer papers will not matter much, even if a certain brand of paper will have some unique texture/feel. Some people swear by the Moleskine notebooks, but a lot of others seem content buying any reasonably high-quality notebooks. I personally don't have brand loyalty in things like toothpaste. So what makes Coke so special as opposed to yet another soda drink?