An interesting follow-up to the story of Qibla Cola's failure can be found here in today's Guardian "g2" supplement (third story down), which gives another angle on why the product failed, rather than the one about "Muslims are useless and don't support each other":
At Bangla City, there is an untouched-looking pile of Qibla Cola right by the door, splashed by customers' wet footsteps and reduced in price by a third. "I've got quite a bit left," says Ahmed, "but they've got good dates on them." He looks at one of the fat two-litre bottles. "February 2006." Why does he think Qibla failed, when a lot of Muslims drink Coca-Cola? He looks out of the doorway at the drizzle and begins an explanation about religion, politics and consumerism, but then he grinds to a halt. "Qibla Cola," he says, "is a bit flat".
Puts me in mind of the time I picked up some Qibla Cola in an Islamic book and merchandise shop in east London, and opened them and it didn't really taste that good. It was flat, and too sweet, and didn't make you feel too good after drinking it. I had drunk the stuff out of cans I got from the Golborne Road Indian take-away, and I presumed that this stuff was dodgy, perhaps counterfeit - and the poorly-produced and misspelt packaging led me towards this conclusion. But perhaps this was the real deal, and their product had just deteriorated or perhaps tasted different out of a can.

Assalaamu alaikum,
Well, that's interesting. When I drink cola, I prefer the taste of Coca-Cola, but I tried Mecca Cola and I liked it. I've had Zam-zam cola, and it was OK, but not my favorite. I never heard of Qibla cola until you mentioned it.
We used to get Mecca cola as well - far preferred its taste to Coke or Pepsi. Recently it hasn't been available here - not sure if it suffered the same fate as qibla cola?
I live in Toronto, Canada. I've had Qibla Cola before. I must say, it was a bit flat. It really didn't taste very good at all.
I've had Mecca cola as well but no Zam-zam cola. The Mecca cola didn't taste that bad. But it didn't taste particularly good either.
Honestly, sometimes I catch myself drinking Coke or Pepsi and think: carbonated beverages aren't very pleasant to drink except out of habit or something...
Yeah, I've never understood what's the deal with these carbonated drinks. I've never been a big fan. In fact, I refuse to drink that stuff. Fruit juice tastes so much better - and it's much more authentic.
I think the point is, if you're going to make a product - before releasing it make sure it actually tastes nice! Coca-Cola wouldn't be successful if it tasted yak so it kinda makes sense.