Pretty much everyone has a preference between Coke and Pepsi, even though most people can't tell the difference. So what is the difference?

"Pepsi is sweeter than Coke, so right away it had a big advantage in a sip test. Pepsi is also characterized by a citrusy flavor burst, unlike the more raisiny-vanilla taste of Coke. But that burst tends to dissipate over the course of an entire can, and that is another reason Coke suffered by comparison. Pepsi, in short, is a drink built to shine in a sip test," writes Malcom Gladwell in Blink, explaining why Pepsi tends to win the Pepsi Challenge Turning to nutritional content, Pepsi has slightly more sugar, calories, and caffeine. Coke has slightly more sodium. There are also mysterious differences in the natural flavors included in each drink.  

Despite these differences, most people can't tell the difference, according to a study by Samuel McClure and Read Montague: "Coke and Pepsi are special in that, while they have very similar chemical composition, people maintain strong behavioral preferences for one over the other. We initially measured these behavioral preferences objectively, by administering double-blind taste tests. We found that subjects split equally in their preferences for Coke and Pepsi in the absence of brand information."

What really matters is branding, and Coke Brand most valubale.. That's why Coke is winning the Cola war. In 2011, Coke brand held 17 percent of the US soda market, followed by Diet Coke at 9.6 percent and Pepsi at 9.2 percent, according to Beverage Digest. Meanwhile Diet Pepsi languishes at 4.9 percent after a dearth of ad spending.