The discussion continues and will likely never go away completely. I was one of the first to research and write about this on the site almost 10 years ago, and the best answer, recently supported by a fish physiologist (Dr. Bruce Tufts), is that it's the carbon dioxide in the drink, which means it doesn't matter which brand of cola you use, and even something as simple as plain carbonated water could be effective. The higher the content, the better, most likely.
Regardless, upon further studying, it turns out that CO2 is weird in that in nearly all cases, it acts as a vasodilator in people. The one exception is the lungs, where it acts as a vasoconstrictor. The belief is that the gills in fish are acting like the lungs in people, and the blood vessels feeding them immediately constrict when met with high CO2 contact. However, more current articles still continue to mention cauterization, which is a different process, and potentially more 'significant' in its effects on tissue.
Still, this is the best "scientific" answer I've seen to date, though no one has addressed if there are any negative consequences to the practice.
Made it out to a local reservoir yesterday to chase bass. Overall, the bite was slow, with just over half a dozen bites each afternoon, but the quality was pretty good, a common theme this time of year. Lots of ways to approach this game, and everyone ultimately falls into a routine for the most part. Worst thing you can do (IMHO) is chase all the Internet hype and "professional" stories, as half of it is sponsor promotions and the other half is marketing. Yes, there's some good info in there at times if you can separate the hype from the salesmanship - it's not as easy as you might think. These days, I go simple or I go "old school," the latter being structure fishing, ala Buck Perry stuff - structure, breaks and breaklines. You can do whatever you want :)
Out on the boat for a shakedown now that the weather is beginning to look like it might cooperate with spring bass anglers. Just a few bites, but a couple solid keepers, and a nicer fish over 4 pounds. Good start for the boat this year.