It's inevitable. You write articles about pianists, crustaceans, comedians, and mobile virtual network operators, and you get reader e-mails asking you to solve the world's problems. This week's most pressing query: Why did Coca Cola bring out the zero-calorie Coca Cola Zero when they just could have replaced aftertasty Diet Coke? Hmm. I haven't had traditional soda in a few years, but I have recently been taste-testing the Zero, and I must say, it's one sweet ride to chillsville; it does send me into hallunicinatory states where I'm singing on top of Brooklyn mid-rises with cadres of my multinational friends. Anyway, here, a priori, is my take: CC Zero won't ever make use of Splenda, the new sweetener that's rendering newer versions of Diet Coke slightly less rancid by the hour. And since certain soda lovers --diabetics, low-carbers, crazy people who don't want cancer, etc. -- benefit from Splenda-sweetened drinks, the two beverages will have to coexist for some time. If not forever! So get used to it, carbonation-hounds. Get used to it, now. And by all means, don't view this as a reason to stop drinking the water. Water heals, yo.