I'm not saying they got it right, 237SJ. I can't really think who might like the taste of Coke Zero; but I'm not their target audience anyway. But it's been selling for almost 10 years, so I suppose it's doing okay.
Apparently Diet Coke was supposed to taste different from the Real Thing but Zero was supposed to taste the same. Only I don't like either of them, but am happier with Diet Coke. (I don't like the various Pepsi lights either, which is a shame because it's very much cheaper than Coke at Costco).
http://en.wikipedia.org/wiki/Coca-Cola_Zero